4277 files changed, 99127 insertions, 59791 deletions

diff --git a/spec/ruby/.mspec.constants b/spec/ruby/.mspec.constants
index d7e09ca2d9..4da3633715 100644
--- a/spec/ruby/.mspec.constants
+++ b/spec/ruby/.mspec.constants
@@ -39,8 +39,11 @@ CodingUS_ASCII
 CodingUTF_8
 ComparisonTest
 ConstantSpecsIncludedModule
+ConstantSpecsTwo
+ConstantSpecsThree
 ConstantVisibility
 Coverage
+CoverageSpecs
 CustomArgumentError
 DRb
 DRbIdConv
@@ -72,6 +75,7 @@ EvalBindingProcA
 Exception2MessageMapper
 ExceptionForMatrix
 Fcntl
+Fiddle
 FileStat
 FileUtils
 Find
@@ -142,6 +146,7 @@ Prime
 Private
 ProcFromMethod
 Psych
+RactorLocalSingleton
 REXML
 RUBY_SIGNALS
 RbReadline
@@ -152,6 +157,7 @@ RegexpSpecsSubclassTwo
 Reline
 RescueInClassExample
 Resolv
+Ripper
 SHA1Constants
 SHA256Constants
 SHA384Constants
@@ -199,6 +205,7 @@ UserArray
 UserCustomConstructorString
 UserDefined
 UserDefinedImmediate
+UserDefinedString
 UserDefinedWithIvar
 UserHash
 UserHashInitParams
diff --git a/spec/ruby/.rubocop.yml b/spec/ruby/.rubocop.yml
index c522f6325a..0b5dcb80a2 100644
--- a/spec/ruby/.rubocop.yml
+++ b/spec/ruby/.rubocop.yml
@@ -1,11 +1,16 @@
 inherit_from: .rubocop_todo.yml
 
 AllCops:
-  TargetRubyVersion: 2.4
+  TargetRubyVersion: 3.2
   DisplayCopNames: true
   Exclude:
     - command_line/fixtures/bad_syntax.rb
+    - core/exception/fixtures/syntax_error.rb
   DisabledByDefault: true
+  NewCops: disable
+
+Layout/IndentationConsistency:
+  Enabled: true
 
 Layout/TrailingWhitespace:
   Enabled: true
@@ -15,6 +20,10 @@ Layout/TrailingEmptyLines:
   Exclude:
     - library/coverage/fixtures/some_class.rb
 
+Layout/SpaceInLambdaLiteral:
+  Enabled: true
+  EnforcedStyle: require_space
+
 Lint:
   Enabled: true
 
@@ -28,18 +37,29 @@ Lint/AssignmentInCondition:
 Lint/BooleanSymbol:
   Enabled: false
 
+Lint/DeprecatedOpenSSLConstant:
+  Exclude:
+    - library/openssl/digest/**/*.rb
+
 Lint/InterpolationCheck:
   Enabled: false
 
 Lint/LiteralAsCondition:
   Enabled: false
 
+# Required to support Ruby 3.0
 Lint/RedundantRequireStatement:
-  Enabled: false
+  Exclude:
+    - core/fiber/**/*.rb
+    - library/fiber/**/*.rb
+    - optional/capi/fiber_spec.rb
 
 Lint/RedundantSplatExpansion:
   Enabled: false
 
+Lint/RescueException:
+  Enabled: false
+
 Lint/UnifiedInteger:
   Enabled: false
 
@@ -52,12 +72,58 @@ Lint/UnusedMethodArgument:
 Lint/UselessAssignment:
   Enabled: false
 
-Lint/UselessComparison:
+Lint/BinaryOperatorWithIdenticalOperands:
   Enabled: false
 
+Lint/EmptyConditionalBody:
+  Enabled: false # buggy
+
 Lint/Void:
   Enabled: false
 
+Lint/ConstantDefinitionInBlock:
+  Enabled: false
+
+Lint/RaiseException:
+  Enabled: false
+
+Lint/FloatComparison:
+  Enabled: false
+
+Lint/DeprecatedClassMethods:
+  Enabled: false
+
+Lint/UnreachableLoop:
+  Enabled: false
+
+Lint/MissingSuper:
+  Enabled: false
+
+Lint/UselessMethodDefinition:
+  Enabled: false
+
+Lint/UselessTimes:
+  Enabled: false
+
+Lint/MixedRegexpCaptureTypes:
+  Enabled: false
+
+Lint/DuplicateElsifCondition:
+  Enabled: false
+
+Lint/OutOfRangeRegexpRef:
+  Enabled: false
+
+Lint/InheritException:
+  Enabled: false
+
+Lint/SafeNavigationChain:
+  Enabled: false
+
+Lint/ElseLayout:
+  Exclude:
+    - 'language/if_spec.rb'
+
 Lint/EmptyExpression:
   Exclude:
     - 'language/**/*.rb'
@@ -67,6 +133,10 @@ Lint/EmptyWhen:
     - language/case_spec.rb
     - optional/capi/spec_helper.rb
 
+Lint/ErbNewArguments:
+  Exclude:
+    - 'library/erb/new_spec.rb'
+
 Lint/FormatParameterMismatch:
   Exclude:
     - 'core/kernel/shared/sprintf.rb'
@@ -88,8 +158,10 @@ Lint/UnreachableCode:
   Exclude:
     - 'core/enumerator/lazy/fixtures/classes.rb'
     - 'core/kernel/catch_spec.rb'
+    - 'core/kernel/raise_spec.rb'
     - 'core/kernel/throw_spec.rb'
     - 'language/break_spec.rb'
+    - 'language/optional_assignments_spec.rb'
     - 'language/fixtures/break.rb'
     - 'language/fixtures/break_lambda_toplevel.rb'
     - 'language/fixtures/break_lambda_toplevel_block.rb'
@@ -108,6 +180,12 @@ Lint/Debugger:
   Exclude:
     - 'core/binding/fixtures/irb.rb'
 
+Lint/Loop:
+  Enabled: false
+
+Style/BlockComments:
+  Enabled: true
+
 Style/Lambda:
   Enabled: true
   EnforcedStyle: literal
@@ -115,6 +193,7 @@ Style/Lambda:
     - 'language/lambda_spec.rb'
     - 'language/proc_spec.rb'
     - 'language/numbered_parameters_spec.rb'
+    - 'language/it_parameter_spec.rb'
     - 'core/kernel/lambda_spec.rb'
 
 Style/EmptyLambdaParameter:
diff --git a/spec/ruby/.rubocop_todo.yml b/spec/ruby/.rubocop_todo.yml
index 36e41aec87..f998002c6d 100644
--- a/spec/ruby/.rubocop_todo.yml
+++ b/spec/ruby/.rubocop_todo.yml
@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2019-12-12 22:16:26 +0900 using RuboCop version 0.77.0.
+# on 2026-05-29 08:10:07 UTC using RuboCop version 1.86.2.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -11,14 +11,20 @@ Lint/DuplicateCaseCondition:
   Exclude:
     - 'language/case_spec.rb'
 
-# Offense count: 6
+# Offense count: 20
 Lint/DuplicateMethods:
   Exclude:
     - 'core/array/fixtures/encoded_strings.rb'
     - 'core/method/fixtures/classes.rb'
+    - 'core/module/const_added_spec.rb'
+    - 'core/module/define_method_spec.rb'
     - 'core/module/fixtures/classes.rb'
+    - 'core/module/method_added_spec.rb'
+    - 'core/module/name_spec.rb'
+    - 'core/proc/new_spec.rb'
     - 'core/unboundmethod/fixtures/classes.rb'
     - 'fixtures/class.rb'
+    - 'language/assignments_spec.rb'
 
 # Offense count: 8
 Lint/EnsureReturn:
@@ -38,9 +44,11 @@ Lint/FloatOutOfRange:
   Exclude:
     - 'core/string/modulo_spec.rb'
 
-# Offense count: 2
+# Offense count: 3
+# This cop supports safe autocorrection (--autocorrect).
 Lint/ImplicitStringConcatenation:
   Exclude:
+    - 'core/string/chilled_string_spec.rb'
     - 'language/string_spec.rb'
 
 # Offense count: 4
@@ -50,76 +58,53 @@ Lint/IneffectiveAccessModifier:
     - 'core/module/fixtures/classes.rb'
     - 'language/fixtures/private.rb'
 
-# Offense count: 6
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: runtime_error, standard_error
-Lint/InheritException:
-  Exclude:
-    - 'core/enumerator/lazy/fixtures/classes.rb'
-    - 'core/exception/fixtures/common.rb'
-    - 'core/module/fixtures/autoload_ex1.rb'
-
-# Offense count: 72
-# Cop supports --auto-correct.
+# Offense count: 12
+# This cop supports safe autocorrection (--autocorrect).
 Lint/LiteralInInterpolation:
   Exclude:
     - 'core/module/refine_spec.rb'
-    - 'core/regexp/shared/new.rb'
     - 'core/string/shared/to_sym.rb'
     - 'language/alias_spec.rb'
     - 'language/defined_spec.rb'
     - 'language/fixtures/squiggly_heredoc.rb'
+    - 'language/string_spec.rb'
     - 'language/symbol_spec.rb'
     - 'language/undef_spec.rb'
-    - 'library/net/ftp/connect_spec.rb'
-
-# Offense count: 16
-Lint/Loop:
-  Exclude:
-    - 'language/until_spec.rb'
-    - 'language/while_spec.rb'
 
 # Offense count: 8
-# Cop supports --auto-correct.
+# This cop supports safe autocorrection (--autocorrect).
 Lint/MultipleComparison:
   Exclude:
     - 'language/precedence_spec.rb'
 
 # Offense count: 9
+# This cop supports safe autocorrection (--autocorrect).
 Lint/ParenthesesAsGroupedExpression:
   Exclude:
-    - 'core/string/fixtures/freeze_magic_comment.rb'
     - 'language/block_spec.rb'
-    - 'language/fixtures/send.rb'
     - 'language/method_spec.rb'
 
+# Offense count: 1
+# This cop supports unsafe autocorrection (--autocorrect-all).
+# Configuration parameters: AllowedMethods, InferNonNilReceiver, AdditionalNilMethods.
+# AllowedMethods: instance_of?, kind_of?, is_a?, eql?, respond_to?, equal?
+# AdditionalNilMethods: present?, blank?, try, try!
+Lint/RedundantSafeNavigation:
+  Exclude:
+    - 'language/safe_navigator_spec.rb'
+    - 'language/fixtures/rescue_captures.rb'
+
 # Offense count: 2
-# Cop supports --auto-correct.
+# This cop supports safe autocorrection (--autocorrect).
 Lint/RedundantStringCoercion:
   Exclude:
     - 'core/io/print_spec.rb'
 
 # Offense count: 1
-# Cop supports --auto-correct.
-Lint/RedundantWithIndex:
-  Exclude:
-    - 'core/enumerator/with_index_spec.rb'
-
-# Offense count: 22
-Lint/RescueException:
-  Exclude:
-    - 'command_line/fixtures/debug_info.rb'
-    - 'core/dir/fileno_spec.rb'
-    - 'core/exception/cause_spec.rb'
-    - 'core/exception/no_method_error_spec.rb'
-    - 'core/kernel/fixtures/autoload_frozen.rb'
-    - 'core/module/autoload_spec.rb'
-    - 'core/mutex/sleep_spec.rb'
-    - 'core/thread/abort_on_exception_spec.rb'
-    - 'core/thread/shared/exit.rb'
-    - 'language/rescue_spec.rb'
-    - 'library/erb/filename_spec.rb'
+# Configuration parameters: AllowRBSInlineAnnotation.
+Lint/SelfAssignment:
+  Exclude:
+    - 'core/gc/auto_compact_spec.rb'
 
 # Offense count: 4
 # Configuration parameters: IgnoreImplicitReferences.
@@ -127,8 +112,8 @@ Lint/ShadowedArgument:
   Exclude:
     - 'language/fixtures/super.rb'
 
-# Offense count: 39
-# Configuration parameters: AllowComments.
+# Offense count: 49
+# Configuration parameters: AllowComments, AllowNil.
 Lint/SuppressedException:
   Enabled: false
 
@@ -140,7 +125,8 @@ Lint/UnderscorePrefixedVariableName:
     - 'core/io/popen_spec.rb'
     - 'language/block_spec.rb'
 
-# Offense count: 7
+# Offense count: 9
+# This cop supports safe autocorrection (--autocorrect).
 # Configuration parameters: ContextCreatingMethods, MethodCreatingMethods.
 Lint/UselessAccessModifier:
   Exclude:
@@ -148,4 +134,5 @@ Lint/UselessAccessModifier:
     - 'core/module/fixtures/classes.rb'
     - 'core/module/module_function_spec.rb'
     - 'core/module/private_class_method_spec.rb'
+    - 'language/fixtures/def.rb'
     - 'language/fixtures/send.rb'
diff --git a/spec/ruby/CONTRIBUTING.md b/spec/ruby/CONTRIBUTING.md
index 1ec6f0ff4b..a474e205f0 100644
--- a/spec/ruby/CONTRIBUTING.md
+++ b/spec/ruby/CONTRIBUTING.md
@@ -8,17 +8,19 @@ Spec are grouped in 5 separate top-level groups:
 
 * `command_line`: for the ruby executable command-line flags (`-v`, `-e`, etc)
 * `language`: for the language keywords and syntax constructs (`if`, `def`, `A::B`, etc)
-* `core`: for the core methods (`Fixnum#+`, `String#upcase`, no need to require anything)
+* `core`: for the core methods (`Integer#+`, `String#upcase`, no need to require anything)
 * `library`: for the standard libraries methods (`CSV.new`, `YAML.parse`, need to require the stdlib)
 * `optional/capi`: for functions available to the Ruby C-extension API
 
 The exact file for methods is decided by the `#owner` of a method, for instance for `#group_by`:
+
 ```ruby
 > [].method(:group_by)
 => #<Method: Array(Enumerable)#group_by>
 > [].method(:group_by).owner
 => Enumerable
 ```
+
 Which should therefore be specified in `core/enumerable/group_by_spec.rb`.
 
 ### MkSpec - a tool to generate the spec structure
@@ -53,12 +55,19 @@ which indicates the file was generated but the method unspecified.
 Here is a list of frequently-used matchers, which should be enough for most specs.
 There are a few extra specific matchers used in the couple specs that need it.
 
+The general idea is: add `.should` just before the predicate you expect to be truthy, and done!
+This works for most needs and provides a great error when it fails.
+It's immediately clear which method is used and there no need to remember a mapping like in RSpec between e.g. `eq` and `==`.
+See [this blog post](https://eregon.me/blog/2019/10/07/a-new-should-syntax.html) for the motivation behind that syntax.
+
+#### Comparison matchers
+
 ```ruby
 (1 + 2).should == 3 # Calls #==
 (1 + 2).should_not == 5
 
-File.should equal(File) # Calls #equal? (tests identity)
-(1 + 2).should eql(3) # Calls #eql? (Hash equality)
+File.should.equal?(File) # Calls #equal? (tests identity)
+(1 + 2).should.eql?(3) # Calls #eql? (Hash equality)
 
 1.should < 2
 2.should <= 2
@@ -66,40 +75,55 @@ File.should equal(File) # Calls #equal? (tests identity)
 4.should > 3
 
 "Hello".should =~ /l{2}/ # Calls #=~ (Regexp match)
+```
 
-[].should be_empty # Calls #empty?
-[1,2,3].should include(2) # Calls #include?
+#### Predicate matchers
+
+```ruby
+[].should.empty?
+[1,2,3].should.include?(2)
+
+"hello".should.start_with?("h")
+"hello".should.end_with?("o")
 
 (0.1 + 0.2).should be_close(0.3, TOLERANCE) # (0.2-0.1).abs < TOLERANCE
-(0.0/0.0).should be_nan # Calls Float#nan?
-(1.0/0.0).should be_positive_infinity
-(-1.0/0.0).should be_negative_infinity
+(0.0/0.0).should.nan?
 
-3.14.should be_an_instance_of(Float) # Calls #instance_of?
-3.14.should be_kind_of(Numeric) # Calls #is_a?
-Numeric.should be_ancestor_of(Float) # Float.ancestors.include?(Numeric)
+3.14.should.instance_of?(Float) # Calls #instance_of?
+3.14.should.is_a?(Numeric) # Calls #is_a?
 
-3.14.should respond_to(:to_i) # Calls #respond_to?
-Fixnum.should have_instance_method(:+)
-Array.should have_method(:new)
-# Also have_constant, have_private_instance_method, have_singleton_method, etc
+3.14.should.respond_to?(:to_i)
+Integer.should.method_defined?(:+, false)
+```
 
+#### Exception matchers
+
+```ruby
 -> {
   raise "oops"
-}.should raise_error(RuntimeError, /oops/)
+}.should.raise(RuntimeError, /oops/)
 
 -> {
   raise "oops"
-}.should raise_error(RuntimeError) { |e|
+}.should.raise(RuntimeError) { |e|
   # Custom checks on the Exception object
-  e.message.should include("oops")
+  e.message.should.include?("oops")
   e.cause.should == nil
 }
+```
+
+##### `should_not.raise`
+
+**Avoid this!** Instead, use an expectation testing what the code in the lambda does.
+If an exception is raised, it will fail the example anyway.
+
+```ruby
+-> { ... }.should_not.raise
+```
 
-# To avoid! Instead, use an expectation testing what the code in the lambda does.
-# If an exception is raised, it will fail the example anyway.
--> { ... }.should_not raise_error
+#### Warning matcher
 
+```ruby
 -> {
   Fixnum
 }.should complain(/constant ::Fixnum is deprecated/) # Expect a warning
@@ -110,15 +134,21 @@ Array.should have_method(:new)
 Different guards are available as defined by mspec.
 Here is a list of the most commonly-used guards:
 
+#### Version guards
+
 ```ruby
-ruby_version_is ""..."2.4" do
-  # Specs for RUBY_VERSION < 2.4
+ruby_version_is ""..."3.2" do
+  # Specs for RUBY_VERSION < 3.2
 end
 
-ruby_version_is "2.4" do
-  # Specs for RUBY_VERSION >= 2.4
+ruby_version_is "3.2" do
+  # Specs for RUBY_VERSION >= 3.2
 end
+```
+
+#### Platform guards
 
+```ruby
 platform_is :windows do
   # Specs only valid on Windows
 end
@@ -133,34 +163,48 @@ end
 platform_is_not :linux, :darwin do # Not Linux and not Darwin
 end
 
-platform_is wordsize: 64 do
+platform_is pointer_size: 64 do
   # 64-bit platform
 end
 
 big_endian do
   # Big-endian platform
 end
+```
+
+#### Guard for bug
+
+In case there is a bug in MRI and the fix will be backported to previous versions.
+If it is not backported or not likely, use `ruby_version_is` instead.
+First, file a bug at https://bugs.ruby-lang.org/.
+The problem is `ruby_bug` would make non-MRI implementations fail this spec while MRI itself does not pass it, so it should only be used if the bug is/will be fixed and backported.
+Otherwise, non-MRI implementations would have to choose between being incompatible with the latest release of MRI (which has the bug) to pass the spec, or behave the same as the latest release of MRI (which has the bug) and fail the spec, both which make no sense.
 
-# In case there is a bug in MRI but the expected behavior is obvious
-# First file a bug at https://bugs.ruby-lang.org/
-# It is better to use a ruby_version_is guard if there was a release with the fix
-ruby_bug '#13669', ''...'2.5' do
+IOW, `ruby_bug '#NN', ''...'X.Y' do` is equivalent to `guard_not { RUBY_ENGINE == "ruby" && ruby_version_is ''...'X.Y' } do`. So it skips tests on MRI on specified versions (where a bug is present) and runs tests on alternative implementations only.
+
+```ruby
+ruby_bug '#13669', ''...'3.2' do
   it "works like this" do
     # Specify the expected behavior here, not the bug
   end
 end
+```
 
+#### Combining guards
 
-# Combining guards
-guard -> { platform_is :windows and ruby_version_is ""..."2.5" } do
-  # Windows and RUBY_VERSION < 2.5
+```ruby
+guard -> { platform_is :windows and ruby_version_is ""..."3.2" } do
+  # Windows and RUBY_VERSION < 3.2
 end
 
-guard_not -> { platform_is :windows and ruby_version_is ""..."2.5" } do
+guard_not -> { platform_is :windows and ruby_version_is ""..."3.2" } do
   # The opposite
 end
+```
+
+#### Custom guard
 
-# Custom guard
+```ruby
 max_uint = (1 << 32) - 1
 guard -> { max_uint <= fixnum_max } do
 end
@@ -168,6 +212,8 @@ end
 
 Custom guards are better than a simple `if` as they allow [mspec commands](https://github.com/ruby/mspec/issues/30#issuecomment-312487779) to work properly.
 
+#### Implementation-specific behaviors
+
 In general, the usage of guards should be minimized as possible.
 
 There are no guards to define implementation-specific behavior because
@@ -179,11 +225,11 @@ If an implementation does not support some feature, simply tag the related specs
 ### Shared Specs
 
 Often throughout Ruby, identical functionality is used by different methods and modules. In order
-to avoid duplication of specs, we have shared specs that are re-used in other specs.  The use is a
+to avoid duplication of specs, we have shared specs that are re-used in other specs. The use is a
 bit tricky however, so let's go over it.
 
 Commonly, if a shared spec is only reused within its own module, the shared spec will live within a
-shared directory inside that module's directory. For example, the `core/hash/shared/key.rb` spec is
+shared directory inside that module's directory. For example, the `core/hash/shared/iteration.rb` spec is
 only used by `Hash` specs, and so it lives inside `core/hash/shared/`.
 
 When a shared spec is used across multiple modules or classes, it lives within the `shared/` directory.
@@ -191,54 +237,54 @@ An example of this is the `shared/file/socket.rb` which is used by `core/file/so
 `core/filetest/socket_spec.rb`, and `core/file/state/socket_spec.rb` and so it lives in the root `shared/`.
 
 Defining a shared spec involves adding a `shared: true` option to the top-level `describe` block. This
-will signal not to run the specs directly by the runner.  Shared specs have access to two instance
+will signal not to run the specs directly by the runner. Shared specs have access to two instance
 variables from the implementor spec: `@method` and `@object`, which the implementor spec will pass in.
 
 Here's an example of a snippet of a shared spec and two specs which integrates it:
 
 ```ruby
-# core/hash/shared/key.rb
-describe :hash_key_p, shared: true do
-  it "returns true if the key's matching value was false" do
-    { xyz: false }.send(@method, :xyz).should == true
+# core/hash/shared/iteration.rb
+describe :hash_iteration_no_block, shared: true do
+  it "returns an Enumerator if called on a non-empty hash without a block" do
+    { 1 => 2 }.send(@method).should.instance_of?(Enumerator)
   end
 end
 
-# core/hash/key_spec.rb
-describe "Hash#key?" do
-  it_behaves_like :hash_key_p, :key?
+# core/hash/select_spec.rb
+describe "Hash#select" do
+  it_behaves_like :hash_iteration_no_block, :select
 end
 
-# core/hash/include_spec.rb
-describe "Hash#include?" do
-  it_behaves_like :hash_key_p, :include?
+# core/hash/reject_spec.rb
+describe "Hash#reject" do
+  it_behaves_like :hash_iteration_no_block, :reject
 end
 ```
 
-In the example, the first `describe` defines the shared spec `:hash_key_p`, which defines a spec that
-calls the `@method` method with an expectation.  In the implementor spec, we use `it_behaves_like` to
-integrate the shared spec.  `it_behaves_like` takes 3 parameters: the key of the shared spec, a method,
-and an object.  These last two parameters are accessible via `@method` and `@object` in the shared spec.
+In the example, the first `describe` defines the shared spec `:hash_iteration_no_block`, which defines a spec that
+calls the `@method` method with an expectation. In the implementor spec, we use `it_behaves_like` to
+integrate the shared spec. `it_behaves_like` takes 3 parameters: the key of the shared spec, a method,
+and an object. These last two parameters are accessible via `@method` and `@object` in the shared spec.
 
 Sometimes, shared specs require more context from the implementor class than a simple object. We can address
-this by passing a lambda as the method, which will have the scope of the implementor.  Here's an example of
+this by passing a lambda as the method, which will have the scope of the implementor. Here's an example of
 how this is used currently:
 
 ```ruby
 describe :kernel_sprintf, shared: true do
   it "raises TypeError exception if cannot convert to Integer" do
-    -> { @method.call("%b", Object.new) }.should raise_error(TypeError)
+    -> { @method.call("%b", Object.new) }.should.raise(TypeError)
   end
 end
 
 describe "Kernel#sprintf" do
-  it_behaves_like :kernel_sprintf, -> (format, *args) {
+  it_behaves_like :kernel_sprintf, -> format, *args {
     sprintf(format, *args)
   }
 end
 
 describe "Kernel.sprintf" do
-  it_behaves_like :kernel_sprintf, -> (format, *args) {
+  it_behaves_like :kernel_sprintf, -> format, *args {
     Kernel.sprintf(format, *args)
   }
 end
diff --git a/spec/ruby/README.md b/spec/ruby/README.md
index b34e6681b1..b259a97e21 100644
--- a/spec/ruby/README.md
+++ b/spec/ruby/README.md
@@ -1,11 +1,11 @@
 # The Ruby Spec Suite
 
-[![Actions Build Status](https://github.com/ruby/spec/workflows/CI/badge.svg?branch=master)](https://github.com/ruby/spec/actions)
-[![Windows Actions Build Status](https://github.com/ruby/spec/workflows/Windows/badge.svg?branch=master)](https://github.com/ruby/spec/actions)
-[![Gitter](https://badges.gitter.im/ruby/spec.svg)](https://gitter.im/ruby/spec)
+[![Actions Build Status](https://github.com/ruby/spec/workflows/CI/badge.svg)](https://github.com/ruby/spec/actions)
 
 The Ruby Spec Suite, abbreviated `ruby/spec`, is a test suite for the behavior of the Ruby programming language.
 
+### Description and Motivation
+
 It is not a standardized specification like the ISO one, and does not aim to become one.
 Instead, it is a practical tool to describe and test the behavior of Ruby with code.
 
@@ -17,39 +17,54 @@ Every example code has a textual description, which presents several advantages:
 
 The specs are written with syntax similar to RSpec 2.
 They are run with MSpec, the purpose-built framework for running the Ruby Spec Suite.
-For more information, see the [MSpec](http://github.com/ruby/mspec) project.
+For more information, see the [MSpec](https://github.com/ruby/mspec) project.
 
 The specs describe the [language syntax](language/), the [core library](core/), the [standard library](library/), the [C API for extensions](optional/capi) and the [command line flags](command_line/).
 The language specs are grouped by keyword while the core and standard library specs are grouped by class and method.
 
 ruby/spec is known to be tested in these implementations for every commit:
-* [MRI](http://rubyci.org/) on 30 platforms and 4 versions
+
+* [MRI](https://rubyci.org/) on 30 platforms and 4 versions
 * [JRuby](https://github.com/jruby/jruby/tree/master/spec/ruby) for both 1.7 and 9.x
-* [TruffleRuby](https://github.com/oracle/truffleruby/tree/master/spec/ruby)
+* [TruffleRuby](https://github.com/truffleruby/truffleruby/tree/master/spec/ruby)
 * [Opal](https://github.com/opal/opal/tree/master/spec)
+* [Artichoke](https://github.com/artichoke/spec/tree/artichoke-vendor)
 
-ruby/spec describes the behavior of Ruby 2.4 and more recent Ruby versions.
-More precisely, every latest stable MRI release should [pass](https://travis-ci.org/ruby/spec) all specs of ruby/spec (2.4.x, 2.5.x, 2.6.x, 2.7.x, etc), and those are tested in TravisCI.
+ruby/spec describes the behavior of Ruby 3.3 and more recent Ruby versions.
+More precisely, every latest stable MRI release should [pass](https://github.com/ruby/spec/actions/workflows/ci.yml) all specs of ruby/spec (3.3.x, 3.4.x, etc), and those are tested in CI.
 
-The specs are synchronized both ways around once a month by @eregon between ruby/spec, MRI, JRuby and TruffleRuby.
+### Synchronization with Ruby Implementations
+
+The specs are synchronized both ways around once a month by @andrykonchin between ruby/spec, MRI, JRuby and TruffleRuby,
+using [this script](https://github.com/ruby/mspec/blob/master/tool/sync/sync-rubyspec.rb).
 Each of these repositories has a full copy of the specs under `spec/ruby` to ease editing specs.
 Any of these repositories can be used to add or edit specs, use what is most convenient for you.
 
-For *testing* a Ruby implementation, one should always test against the implementation's copy of the specs under `spec/ruby`, as that's what the Ruby implementation tests against in their CI.
+For *testing* the development version of a Ruby implementation, one should always test against that implementation's copy of the specs under `spec/ruby`, as that's what the Ruby implementation tests against in their CI.
 Also, this repository doesn't always contain the latest spec changes from MRI (it's synchronized monthly), and does not contain tags (specs marked as failing on that Ruby implementation).
-Running specs in a Ruby implementation can be done with:
+Running specs on a Ruby implementation can be done with:
 
-```
+```console
 $ cd ruby_implementation/spec/ruby
 # Add ../ruby_implementation/bin in PATH, or pass -t /path/to/bin/ruby
 $ ../mspec/bin/mspec
 ```
 
+### Specs for old Ruby versions
+
 For older specs try these commits:
+
 * Ruby 2.0.0-p647 - [Suite](https://github.com/ruby/spec/commit/245862558761d5abc676843ef74f86c9bcc8ea8d) using [MSpec](https://github.com/ruby/mspec/commit/f90efa068791064f955de7a843e96e2d7d3041c2) (may encounter 2 failures)
 * Ruby 2.1.9 - [Suite](https://github.com/ruby/spec/commit/f029e65241374386077ac500add557ae65069b55) using [MSpec](https://github.com/ruby/mspec/commit/55568ea3918c6380e64db8c567d732fa5781efed)
 * Ruby 2.2.10 - [Suite](https://github.com/ruby/spec/commit/cbaa0e412270c944df0c2532fc500c920dba0e92) using [MSpec](https://github.com/ruby/mspec/commit/d84d7668449e96856c5f6bac8cb1526b6d357ce3)
 * Ruby 2.3.8 - [Suite](https://github.com/ruby/spec/commit/dc733114d8ae66a3368ba3a98422c50147a76ba5) using [MSpec](https://github.com/ruby/mspec/commit/4599bc195fb109f2a482a01c32a7d659518369ea)
+* Ruby 2.4.10 - [Suite](https://github.com/ruby/spec/commit/bce4f2b81d6c31db67cf4d023a0625ceadde59bd) using [MSpec](https://github.com/ruby/mspec/commit/e7eb8aa4c26495b7b461e687d950b96eb08b3ff2)
+* Ruby 2.5.9 - [Suite](https://github.com/ruby/spec/commit/c503335d3d9f6ec6ef24de60a0716c34af69b64f) using [MSpec](https://github.com/ruby/mspec/commit/0091e8a62e954717cd54641f935eaf1403692041)
+* Ruby 2.6.10 - [Suite](https://github.com/ruby/spec/commit/aaf998fb8c92c4e63ad423a2e7ca6e6921818c6e) using [MSpec](https://github.com/ruby/mspec/commit/5e36c684e9e2b92b1187589bba1df22c640a8661)
+* Ruby 2.7.8 - [Suite](https://github.com/ruby/spec/commit/93787e6035c925b593a9c0c6fb0e7e07a6f1df1f) using [MSpec](https://github.com/ruby/mspec/commit/1d8cf64722d8a7529f7cd205be5f16a89b7a67fd)
+* Ruby 3.0.7 - [Suite](https://github.com/ruby/spec/commit/affef93d9940f615e4836f64b011da211f570913) using [MSpec](https://github.com/ruby/mspec/commit/0aabb3e548eb5ea6cad0125f8f46cee34542b6b7)
+* Ruby 3.1.6 - [Suite](https://github.com/ruby/spec/commit/ec960f2389d1c2265d32397fa8afa6d462014efc) using [MSpec](https://github.com/ruby/mspec/commit/484310dbed35b84c74484fd674602f88c42d063a)
+* Ruby 3.2.9 - [Suite](https://github.com/ruby/spec/commit/97f076242b7fc6e60703e6a6053365065cd6fc30) using [MSpec](https://github.com/ruby/mspec/commit/54704795e21128a930af2021c72c49cb87065134)
 
 ### Running the specs
 
@@ -61,7 +76,7 @@ Then move to it:
 
     $ cd spec
 
-Clone [MSpec](http://github.com/ruby/mspec):
+Clone [MSpec](https://github.com/ruby/mspec):
 
     $ git clone https://github.com/ruby/mspec.git ../mspec
 
@@ -116,16 +131,31 @@ MSpec can automatically add new top-level constants in this file with:
 
     $ CHECK_LEAKS=save mspec ../mspec/bin/mspec file
 
+### Running Specs on S390x CPU Architecture
+
+Run the specs with `DFLTCC=0` if you see failing specs related to the zlib library on s390x CPU architecture. The failures can happen with the zlib library applying the patch madler/zlib#410 to enable the deflate algorithm producing a different compressed byte stream.
+
+    $ DFLTCC=0 ../mspec/bin/mspec
+
 ### Contributing and Writing Specs
 
 See [CONTRIBUTING.md](https://github.com/ruby/spec/blob/master/CONTRIBUTING.md) for documentation about contributing and writing specs (guards, matchers, etc).
 
+### Dependencies
+
+These command-line executables are needed to run the specs.
+
+* `echo`
+* `stat` for `core/file/*time_spec.rb`
+* `find` for `core/file/fixtures/file_types.rb` (package `findutils`, not needed on Windows)
+
+The file `/etc/services` is required for socket specs (package `netbase` on Debian, not needed on Windows).
+
 ### Socket specs from rubysl-socket
 
-Most specs under `library/socket` were imported from [the rubysl-socket project](https://github.com/rubysl/rubysl-socket).
+Most specs under `library/socket` were imported from the rubysl-socket project (which is no longer on GitHub).
 The 3 copyright holders of rubysl-socket, Yorick Peterse, Chuck Remes and
-Brian Shirai, [agreed to relicense those specs](https://github.com/rubysl/rubysl-socket/issues/15)
-under the MIT license in ruby/spec.
+Brian Shirai, agreed to relicense those specs under the MIT license in ruby/spec.
 
 ### History and RubySpec
 
@@ -133,5 +163,5 @@ This project was originally born from [Rubinius](https://github.com/rubinius/rub
 The revision history of these specs is available [here](https://github.com/ruby/spec/blob/2b886623/CHANGES.before-2008-05-10).
 These specs were later extracted to their own project, RubySpec, with a specific vision and principles.
 At the end of 2014, Brian Shirai, the creator of RubySpec, decided to [end RubySpec](http://rubinius.com/2014/12/31/matz-s-ruby-developers-don-t-use-rubyspec/).
-A couple months later, the different repositories were merged and [the project was revived](http://eregon.github.io/rubyspec/2015/07/29/rubyspec-is-reborn.html).
+A couple months later, the different repositories were merged and [the project was revived](https://eregon.github.io/rubyspec/2015/07/29/rubyspec-is-reborn.html).
 On 12 January 2016, the name was changed to "The Ruby Spec Suite" for clarity and to let the RubySpec ideology rest in peace.
diff --git a/spec/ruby/bin/rubocop b/spec/ruby/bin/rubocop
new file mode 100755
index 0000000000..0937c47906
--- /dev/null
+++ b/spec/ruby/bin/rubocop
@@ -0,0 +1,12 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require 'bundler/inline'
+
+gemfile do
+  source 'https://rubygems.org'
+
+  gem 'rubocop', '1.86.2'
+end
+
+exec(Gem.bin_path('rubocop', 'rubocop'), *ARGV)
diff --git a/spec/ruby/command_line/backtrace_limit_spec.rb b/spec/ruby/command_line/backtrace_limit_spec.rb
new file mode 100644
index 0000000000..4d57bc268b
--- /dev/null
+++ b/spec/ruby/command_line/backtrace_limit_spec.rb
@@ -0,0 +1,93 @@
+require_relative '../spec_helper'
+
+describe "The --backtrace-limit command line option" do
+  ruby_version_is ""..."3.4" do
+    it "limits top-level backtraces to a given number of entries" do
+      file = fixture(__FILE__ , "backtrace.rb")
+      out = ruby_exe(file, options: "--backtrace-limit=2", args: "top 2>&1", exit_status: 1)
+      out = out.gsub(__dir__, '')
+
+      out.should == <<-MSG
+top
+/fixtures/backtrace.rb:2:in `a': oops (RuntimeError)
+\tfrom /fixtures/backtrace.rb:6:in `b'
+\tfrom /fixtures/backtrace.rb:10:in `c'
+\t ... 2 levels...
+      MSG
+    end
+
+    it "affects Exception#full_message" do
+      file = fixture(__FILE__ , "backtrace.rb")
+      out = ruby_exe(file, options: "--backtrace-limit=2", args: "full_message 2>&1")
+      out = out.gsub(__dir__, '')
+
+      out.should == <<-MSG
+full_message
+/fixtures/backtrace.rb:2:in `a': oops (RuntimeError)
+\tfrom /fixtures/backtrace.rb:6:in `b'
+\tfrom /fixtures/backtrace.rb:10:in `c'
+\t ... 2 levels...
+      MSG
+    end
+
+    it "does not affect Exception#backtrace" do
+      file = fixture(__FILE__ , "backtrace.rb")
+      out = ruby_exe(file, options: "--backtrace-limit=2", args: "backtrace 2>&1")
+      out = out.gsub(__dir__, '')
+
+      out.should == <<-MSG
+backtrace
+/fixtures/backtrace.rb:2:in `a'
+/fixtures/backtrace.rb:6:in `b'
+/fixtures/backtrace.rb:10:in `c'
+/fixtures/backtrace.rb:14:in `d'
+/fixtures/backtrace.rb:29:in `<main>'
+      MSG
+    end
+  end
+
+  ruby_version_is "3.4" do
+    it "limits top-level backtraces to a given number of entries" do
+      file = fixture(__FILE__ , "backtrace.rb")
+      out = ruby_exe(file, options: "--backtrace-limit=2", args: "top 2>&1", exit_status: 1)
+      out = out.gsub(__dir__, '')
+
+      out.should == <<-MSG
+top
+/fixtures/backtrace.rb:2:in 'Object#a': oops (RuntimeError)
+\tfrom /fixtures/backtrace.rb:6:in 'Object#b'
+\tfrom /fixtures/backtrace.rb:10:in 'Object#c'
+\t ... 2 levels...
+      MSG
+    end
+
+    it "affects Exception#full_message" do
+      file = fixture(__FILE__ , "backtrace.rb")
+      out = ruby_exe(file, options: "--backtrace-limit=2", args: "full_message 2>&1")
+      out = out.gsub(__dir__, '')
+
+      out.should == <<-MSG
+full_message
+/fixtures/backtrace.rb:2:in 'Object#a': oops (RuntimeError)
+\tfrom /fixtures/backtrace.rb:6:in 'Object#b'
+\tfrom /fixtures/backtrace.rb:10:in 'Object#c'
+\t ... 2 levels...
+      MSG
+    end
+
+    it "does not affect Exception#backtrace" do
+      file = fixture(__FILE__ , "backtrace.rb")
+      out = ruby_exe(file, options: "--backtrace-limit=2", args: "backtrace 2>&1")
+      out = out.gsub(__dir__, '')
+
+      out.should == <<-MSG
+backtrace
+/fixtures/backtrace.rb:2:in 'Object#a'
+/fixtures/backtrace.rb:6:in 'Object#b'
+/fixtures/backtrace.rb:10:in 'Object#c'
+/fixtures/backtrace.rb:14:in 'Object#d'
+/fixtures/backtrace.rb:29:in '<main>'
+      MSG
+    end
+  end
+end
diff --git a/spec/ruby/command_line/dash_0_spec.rb b/spec/ruby/command_line/dash_0_spec.rb
new file mode 100755
index 0000000000..2ce4f49b5e
--- /dev/null
+++ b/spec/ruby/command_line/dash_0_spec.rb
@@ -0,0 +1,13 @@
+require_relative '../spec_helper'
+
+describe "The -0 command line option" do
+  it "sets $/ and $-0" do
+    ruby_exe("puts $/, $-0", options: "-072").should == ":\n:\n"
+  end
+
+  ruby_version_is "4.0" do
+    it "sets $/ and $-0 as a frozen string" do
+      ruby_exe("puts $/.frozen?, $-0.frozen?", options: "-072").should == "true\ntrue\n"
+    end
+  end
+end
diff --git a/spec/ruby/command_line/dash_a_spec.rb b/spec/ruby/command_line/dash_a_spec.rb
index 9ea135dc76..43d923ce16 100644
--- a/spec/ruby/command_line/dash_a_spec.rb
+++ b/spec/ruby/command_line/dash_a_spec.rb
@@ -6,13 +6,13 @@ describe "The -a command line option" do
   end
 
   it "runs the code in loop conditional on Kernel.gets()" do
-    ruby_exe("puts $F.last", options: "-n -a", escape: true,
+    ruby_exe("puts $F.last", options: "-n -a",
                              args: " < #{@names}").should ==
       "jones\nfield\ngrey\n"
   end
 
   it "sets $-a" do
-    ruby_exe("puts $-a", options: "-n -a", escape: true,
+    ruby_exe("puts $-a", options: "-n -a",
                          args: " < #{@names}").should ==
       "true\ntrue\ntrue\n"
   end
diff --git a/spec/ruby/command_line/dash_e_spec.rb b/spec/ruby/command_line/dash_e_spec.rb
index 9f600eb414..24ed34376d 100644
--- a/spec/ruby/command_line/dash_e_spec.rb
+++ b/spec/ruby/command_line/dash_e_spec.rb
@@ -23,7 +23,7 @@ describe "The -e command line option" do
 
   #needs to test return => LocalJumpError
 
-  describe "with -n and a Fixnum range" do
+  describe "with -n and an Integer range" do
     before :each do
       @script = "-ne 'print if %s' #{fixture(__FILE__, "conditional_range.txt")}"
     end
diff --git a/spec/ruby/command_line/dash_encoding_spec.rb b/spec/ruby/command_line/dash_encoding_spec.rb
index 36ce55af5f..5803d328c1 100644
--- a/spec/ruby/command_line/dash_encoding_spec.rb
+++ b/spec/ruby/command_line/dash_encoding_spec.rb
@@ -25,6 +25,12 @@ describe "The --encoding command line option" do
   end
 
   it "does not accept a third encoding" do
-    ruby_exe(@test_string, options: "--disable-gems --encoding big5:#{@enc2}:utf-32le", args: "2>&1").should =~ /extra argument for --encoding: utf-32le/
+    options = {
+      options: "--disable-gems --encoding big5:#{@enc2}:utf-32le",
+      args: "2>&1",
+      exit_status: 1
+    }
+
+    ruby_exe(@test_string, options).should =~ /extra argument for --encoding: utf-32le/
   end
 end
diff --git a/spec/ruby/command_line/dash_l_spec.rb b/spec/ruby/command_line/dash_l_spec.rb
new file mode 100644
index 0000000000..44a98445f3
--- /dev/null
+++ b/spec/ruby/command_line/dash_l_spec.rb
@@ -0,0 +1,31 @@
+require_relative '../spec_helper'
+
+describe "The -l command line option" do
+  before :each do
+    @names  = fixture __FILE__, "full_names.txt"
+  end
+
+  it "chomps lines with default separator" do
+    ruby_exe('puts $_.end_with?("\n")', options: "-n -l",
+             args: " < #{@names}").should ==
+        "false\nfalse\nfalse\n"
+  end
+
+  it "chomps last line based on $/" do
+    ruby_exe('BEGIN { $/ = "ones\n" }; puts $_', options: "-W0 -n -l",
+             args: " < #{@names}").should ==
+        "alice j\nbob field\njames grey\n"
+  end
+
+  it "sets $\\ to the value of $/" do
+    ruby_exe("puts $\\ == $/", options: "-W0 -n -l",
+             args: " < #{@names}").should ==
+        "true\ntrue\ntrue\n"
+  end
+
+  it "sets $-l" do
+    ruby_exe("puts $-l", options: "-n -l",
+                         args: " < #{@names}").should ==
+      "true\ntrue\ntrue\n"
+  end
+end
diff --git a/spec/ruby/command_line/dash_n_spec.rb b/spec/ruby/command_line/dash_n_spec.rb
index 9d331d6065..1dd9379259 100644
--- a/spec/ruby/command_line/dash_n_spec.rb
+++ b/spec/ruby/command_line/dash_n_spec.rb
@@ -6,19 +6,19 @@ describe "The -n command line option" do
   end
 
   it "runs the code in loop conditional on Kernel.gets()" do
-    ruby_exe("puts $_", options: "-n", escape: true,
+    ruby_exe("puts $_", options: "-n",
                         args: " < #{@names}").should ==
       "alice\nbob\njames\n"
   end
 
   it "only evaluates BEGIN blocks once" do
-    ruby_exe("BEGIN { puts \"hi\" }; puts $_", options: "-n", escape: true,
+    ruby_exe("BEGIN { puts \"hi\" }; puts $_", options: "-n",
                                                args: " < #{@names}").should ==
       "hi\nalice\nbob\njames\n"
   end
 
   it "only evaluates END blocks once" do
-    ruby_exe("puts $_; END {puts \"bye\"}", options: "-n", escape: true,
+    ruby_exe("puts $_; END {puts \"bye\"}", options: "-n",
                                             args: " < #{@names}").should ==
       "alice\nbob\njames\nbye\n"
   end
@@ -29,7 +29,7 @@ describe "The -n command line option" do
     $total += 1
     END { puts $total }
     script
-    ruby_exe(script, options: "-n", escape: true,
+    ruby_exe(script, options: "-n",
                      args: " < #{@names}").should ==
       "3\n"
   end
diff --git a/spec/ruby/command_line/dash_p_spec.rb b/spec/ruby/command_line/dash_p_spec.rb
index 39827c3868..967e3796de 100644
--- a/spec/ruby/command_line/dash_p_spec.rb
+++ b/spec/ruby/command_line/dash_p_spec.rb
@@ -6,13 +6,13 @@ describe "The -p command line option" do
   end
 
   it "runs the code in loop conditional on Kernel.gets() and prints $_" do
-    ruby_exe("$_ = $_.upcase", options: "-p", escape: true,
+    ruby_exe("$_ = $_.upcase", options: "-p",
                                args: " < #{@names}").should ==
       "ALICE\nBOB\nJAMES\n"
   end
 
   it "sets $-p" do
-    ruby_exe("$_ = $-p", options: "-p", escape: true,
+    ruby_exe("$_ = $-p", options: "-p",
                          args: " < #{@names}").should ==
       "truetruetrue"
   end
diff --git a/spec/ruby/command_line/dash_r_spec.rb b/spec/ruby/command_line/dash_r_spec.rb
index b29895bd26..0de9ba2e24 100644
--- a/spec/ruby/command_line/dash_r_spec.rb
+++ b/spec/ruby/command_line/dash_r_spec.rb
@@ -7,7 +7,22 @@ describe "The -r command line option" do
   end
 
   it "requires the specified file" do
-    result = ruby_exe(@script, options: "-r #{@test_file}")
-    result.should include(@test_file + ".rb")
+    out = ruby_exe(@script, options: "-r #{@test_file}")
+    out.should.include?("REQUIRED")
+    out.should.include?(@test_file + ".rb")
+  end
+
+  it "requires the file before parsing the main script" do
+    out = ruby_exe(fixture(__FILE__, "bad_syntax.rb"), options: "-r #{@test_file}", args: "2>&1", exit_status: 1)
+    $?.should_not.success?
+    out.should.include?("REQUIRED")
+    out.should.include?("SyntaxError")
+  end
+
+  it "does not require the file if the main script file does not exist" do
+    out = `#{ruby_exe.to_a.join(' ')} -r #{@test_file} #{fixture(__FILE__, "does_not_exist.rb")} 2>&1`
+    $?.should_not.success?
+    out.should_not.include?("REQUIRED")
+    out.should.include?("No such file or directory")
   end
 end
diff --git a/spec/ruby/command_line/dash_upper_e_spec.rb b/spec/ruby/command_line/dash_upper_e_spec.rb
index b3c6ce262b..5a83962583 100644
--- a/spec/ruby/command_line/dash_upper_e_spec.rb
+++ b/spec/ruby/command_line/dash_upper_e_spec.rb
@@ -31,6 +31,7 @@ describe "ruby -E" do
   it "raises a RuntimeError if used with -U" do
     ruby_exe("p 1",
              options: '-Eascii:ascii -U',
-             args: '2>&1').should =~ /RuntimeError/
+             args: '2>&1',
+             exit_status: 1).should =~ /RuntimeError/
   end
 end
diff --git a/spec/ruby/command_line/dash_upper_f_spec.rb b/spec/ruby/command_line/dash_upper_f_spec.rb
index 967acc2ece..5c10a7140d 100644
--- a/spec/ruby/command_line/dash_upper_f_spec.rb
+++ b/spec/ruby/command_line/dash_upper_f_spec.rb
@@ -6,7 +6,7 @@ describe "the -F command line option" do
   end
 
   it "specifies the field separator pattern for -a" do
-    ruby_exe("puts $F[0]", options: "-naF:", escape: true,
+    ruby_exe("puts $F[0]", options: "-naF:",
                            args: " < #{@passwd}").should ==
       "nobody\nroot\ndaemon\n"
   end
diff --git a/spec/ruby/command_line/dash_upper_i_spec.rb b/spec/ruby/command_line/dash_upper_i_spec.rb
index 4cafb724e3..4005a27d23 100644
--- a/spec/ruby/command_line/dash_upper_i_spec.rb
+++ b/spec/ruby/command_line/dash_upper_i_spec.rb
@@ -6,7 +6,7 @@ describe "The -I command line option" do
   end
 
   it "adds the path to the load path ($:)" do
-    ruby_exe(@script, options: "-I fixtures").should include("fixtures")
+    ruby_exe(@script, options: "-I fixtures").should.include?("fixtures")
   end
 
   it "adds the path at the front of $LOAD_PATH" do
@@ -18,16 +18,16 @@ describe "The -I command line option" do
       idx.should < 2
       idx.should < lines.size-1
     else
-      lines[0].should include("fixtures")
+      lines[0].should.include?("fixtures")
     end
   end
 
   it "adds the path expanded from CWD to $LOAD_PATH" do
-    ruby_exe(@script, options: "-I fixtures").lines.should include "#{Dir.pwd}/fixtures\n"
+    ruby_exe(@script, options: "-I fixtures").lines.should.include? "#{Dir.pwd}/fixtures\n"
   end
 
   it "expands a path from CWD even if it does not exist" do
-    ruby_exe(@script, options: "-I not_exist/not_exist").lines.should include "#{Dir.pwd}/not_exist/not_exist\n"
+    ruby_exe(@script, options: "-I not_exist/not_exist").lines.should.include? "#{Dir.pwd}/not_exist/not_exist\n"
   end
 end
 
@@ -45,7 +45,7 @@ platform_is_not :windows do
     end
 
     it "does not expand symlinks" do
-      ruby_exe(@script, options: "-I #{@symlink}").lines.should include "#{@symlink}\n"
+      ruby_exe(@script, options: "-I #{@symlink}").lines.should.include? "#{@symlink}\n"
     end
   end
 end
diff --git a/spec/ruby/command_line/dash_upper_k_spec.rb b/spec/ruby/command_line/dash_upper_k_spec.rb
index a060eab793..7e71532295 100644
--- a/spec/ruby/command_line/dash_upper_k_spec.rb
+++ b/spec/ruby/command_line/dash_upper_k_spec.rb
@@ -58,8 +58,8 @@ describe 'The -K command line option' do
   end
 
   it "ignores unknown codes" do
-    locale = Encoding.find('locale')
+    external = Encoding.find('external')
     ruby_exe(@test_string, options: '-KZ').should ==
-      [Encoding::UTF_8.name, locale.name, nil].inspect
+      [Encoding::UTF_8.name, external.name, nil].inspect
   end
 end
diff --git a/spec/ruby/command_line/dash_upper_s_spec.rb b/spec/ruby/command_line/dash_upper_s_spec.rb
index 3a28fa2ad2..71c6016659 100644
--- a/spec/ruby/command_line/dash_upper_s_spec.rb
+++ b/spec/ruby/command_line/dash_upper_s_spec.rb
@@ -2,7 +2,8 @@ require_relative '../spec_helper'
 
 describe 'The -S command line option' do
   before :each do
-    @path = [ENV['PATH'], fixture(__FILE__, "bin")].join(':')
+    @bin = fixture(__FILE__, "bin")
+    @path = [ENV['PATH'], @bin].join(File::PATH_SEPARATOR)
   end
 
   platform_is_not :windows do
@@ -10,20 +11,57 @@ describe 'The -S command line option' do
     # and MRI shows warning when including world writable path in ENV['PATH'].
     # This is why we are using /success$/ matching in the following cases.
 
+    it "runs launcher found in RUBYPATH, but only code after the first /\#!.*ruby.*/-ish line in target file" do
+      result = ruby_exe(nil, options: '-S hybrid_launcher.sh', env: { 'RUBYPATH' => @bin }, args: '2>&1')
+      result.should =~ /success$/
+    end
+
     it "runs launcher found in PATH, but only code after the first /\#!.*ruby.*/-ish line in target file" do
       result = ruby_exe(nil, options: '-S hybrid_launcher.sh', env: { 'PATH' => @path }, args: '2>&1')
       result.should =~ /success$/
     end
 
+    it "runs launcher found in RUBYPATH" do
+      result = ruby_exe(nil, options: '-S launcher.rb', env: { 'RUBYPATH' => @bin }, args: '2>&1')
+      result.should =~ /success$/
+    end
+
     it "runs launcher found in PATH" do
       result = ruby_exe(nil, options: '-S launcher.rb', env: { 'PATH' => @path }, args: '2>&1')
       result.should =~ /success$/
     end
 
+    it "runs launcher found in RUBYPATH and sets the exit status to 1 if it fails" do
+      result = ruby_exe(nil, options: '-S dash_s_fail', env: { 'RUBYPATH' => @bin }, args: '2>&1', exit_status: 1)
+      result.should =~ /\bdie\b/
+      $?.exitstatus.should == 1
+    end
+
     it "runs launcher found in PATH and sets the exit status to 1 if it fails" do
-      result = ruby_exe(nil, options: '-S dash_s_fail', env: { 'PATH' => @path }, args: '2>&1')
+      result = ruby_exe(nil, options: '-S dash_s_fail', env: { 'PATH' => @path }, args: '2>&1', exit_status: 1)
       result.should =~ /\bdie\b/
       $?.exitstatus.should == 1
     end
+
+    ruby_version_is "4.1" do
+      describe "if the script name contains separator" do
+        before(:each) do
+          @bin = File.dirname(@bin)
+          @path = [ENV['PATH'], @bin].join(File::PATH_SEPARATOR)
+        end
+
+        it "does not search launcher in RUBYPATH" do
+          result = ruby_exe(nil, options: '-S bin/launcher.rb', env: { 'RUBYPATH' => @bin }, args: '2>&1', exit_status: 1)
+          result.should =~ /LoadError/
+          $?.should_not.success?
+        end
+
+        it "does not search launcher in PATH" do
+          result = ruby_exe(nil, options: '-S bin/launcher.rb', env: { 'PATH' => @path }, args: '2>&1', exit_status: 1)
+          result.should =~ /LoadError/
+          $?.should_not.success?
+        end
+      end
+    end
   end
 end
diff --git a/spec/ruby/command_line/dash_upper_u_spec.rb b/spec/ruby/command_line/dash_upper_u_spec.rb
index 2546b5b9f4..2c210eb603 100644
--- a/spec/ruby/command_line/dash_upper_u_spec.rb
+++ b/spec/ruby/command_line/dash_upper_u_spec.rb
@@ -2,42 +2,51 @@ require_relative '../spec_helper'
 
 describe "ruby -U" do
   it "sets Encoding.default_internal to UTF-8" do
-     ruby_exe('print Encoding.default_internal.name',
-              options: '-U').should == 'UTF-8'
+    ruby_exe('print Encoding.default_internal.name',
+             options: '-U').should == 'UTF-8'
+  end
+
+  it "sets Encoding.default_internal to UTF-8 when RUBYOPT is empty or only spaces" do
+    ruby_exe('p Encoding.default_internal',
+             options: '-U', env: { 'RUBYOPT' => '' }).should == "#<Encoding:UTF-8>\n"
+    ruby_exe('p Encoding.default_internal',
+             options: '-U', env: { 'RUBYOPT' => '  ' }).should == "#<Encoding:UTF-8>\n"
   end
 
   it "does nothing different if specified multiple times" do
-     ruby_exe('print Encoding.default_internal.name',
-              options: '-U -U').should == 'UTF-8'
+    ruby_exe('print Encoding.default_internal.name',
+             options: '-U -U').should == 'UTF-8'
   end
 
   it "is overruled by Encoding.default_internal=" do
-     ruby_exe('Encoding.default_internal="ascii"; print Encoding.default_internal.name',
-              options: '-U').should == 'US-ASCII'
+    ruby_exe('Encoding.default_internal="ascii"; print Encoding.default_internal.name',
+             options: '-U').should == 'US-ASCII'
   end
 
   it "does not affect the default external encoding" do
-     ruby_exe('Encoding.default_external="ascii"; print Encoding.default_external.name',
-              options: '-U').should == 'US-ASCII'
+    ruby_exe('Encoding.default_external="ascii"; print Encoding.default_external.name',
+             options: '-U').should == 'US-ASCII'
   end
 
   it "does not affect the source encoding" do
-     ruby_exe("print __ENCODING__.name",
-              options: '-U -KE').should == 'EUC-JP'
-     ruby_exe("print __ENCODING__.name",
-              options: '-KE -U').should == 'EUC-JP'
+    ruby_exe("print __ENCODING__.name",
+             options: '-U -KE').should == 'EUC-JP'
+    ruby_exe("print __ENCODING__.name",
+             options: '-KE -U').should == 'EUC-JP'
   end
 
   # I assume IO redirection will break on Windows...
   it "raises a RuntimeError if used with -Eext:int" do
     ruby_exe("p 1",
              options: '-U -Eascii:ascii',
-             args: '2>&1').should =~ /RuntimeError/
+             args: '2>&1',
+             exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError if used with -E:int" do
     ruby_exe("p 1",
              options: '-U -E:ascii',
-             args: '2>&1').should =~ /RuntimeError/
+             args: '2>&1',
+             exit_status: 1).should =~ /RuntimeError/
   end
 end
diff --git a/spec/ruby/command_line/dash_upper_w_spec.rb b/spec/ruby/command_line/dash_upper_w_spec.rb
index 31bb976ad2..4019510d42 100644
--- a/spec/ruby/command_line/dash_upper_w_spec.rb
+++ b/spec/ruby/command_line/dash_upper_w_spec.rb
@@ -18,3 +18,27 @@ end
 describe "The -W command line option with 2" do
   it_behaves_like :command_line_verbose, "-W2"
 end
+
+describe "The -W command line option with :deprecated" do
+  it "enables deprecation warnings" do
+    ruby_exe('p Warning[:deprecated]', options: '-W:deprecated').should == "true\n"
+  end
+end
+
+describe "The -W command line option with :no-deprecated" do
+  it "suppresses deprecation warnings" do
+    ruby_exe('p Warning[:deprecated]', options: '-w -W:no-deprecated').should == "false\n"
+  end
+end
+
+describe "The -W command line option with :experimental" do
+  it "enables experimental warnings" do
+    ruby_exe('p Warning[:experimental]', options: '-W:experimental').should == "true\n"
+  end
+end
+
+describe "The -W command line option with :no-experimental" do
+  it "suppresses experimental warnings" do
+    ruby_exe('p Warning[:experimental]', options: '-w -W:no-experimental').should == "false\n"
+  end
+end
diff --git a/spec/ruby/command_line/dash_v_spec.rb b/spec/ruby/command_line/dash_v_spec.rb
index 04d684fdad..6a4f7d3a15 100644
--- a/spec/ruby/command_line/dash_v_spec.rb
+++ b/spec/ruby/command_line/dash_v_spec.rb
@@ -6,7 +6,10 @@ describe "The -v command line option" do
 
   describe "when used alone" do
     it "prints version and ends" do
-      ruby_exe(nil, args: '-v').should include(RUBY_DESCRIPTION)
-    end
+      ruby_exe(nil, args: '-v').gsub("+PRISM ", "").should.include?(RUBY_DESCRIPTION.gsub("+PRISM ", ""))
+    end unless (defined?(RubyVM::YJIT) && RubyVM::YJIT.enabled?) ||
+               (defined?(RubyVM::RJIT) && RubyVM::RJIT.enabled?) ||
+               (ENV['RUBY_GC_LIBRARY'] && ENV['RUBY_GC_LIBRARY'].length > 0) ||
+               (ENV['RUBY_MN_THREADS'] == '1')
   end
 end
diff --git a/spec/ruby/command_line/dash_w_spec.rb b/spec/ruby/command_line/dash_w_spec.rb
index 1d93e0347b..f310dca3ed 100644
--- a/spec/ruby/command_line/dash_w_spec.rb
+++ b/spec/ruby/command_line/dash_w_spec.rb
@@ -3,4 +3,8 @@ require_relative 'shared/verbose'
 
 describe "The -w command line option" do
   it_behaves_like :command_line_verbose, "-w"
+
+  it "enables both deprecated and experimental warnings" do
+    ruby_exe('p Warning[:deprecated]; p Warning[:experimental]', options: '-w').should == "true\ntrue\n"
+  end
 end
diff --git a/spec/ruby/command_line/dash_x_spec.rb b/spec/ruby/command_line/dash_x_spec.rb
index eb89db0144..38f97a5ab1 100644
--- a/spec/ruby/command_line/dash_x_spec.rb
+++ b/spec/ruby/command_line/dash_x_spec.rb
@@ -9,8 +9,8 @@ describe "The -x command line option" do
 
   it "fails when /\#!.*ruby.*/-ish line in target file is not found" do
     bad_embedded_ruby = fixture __FILE__, "bin/bad_embedded_ruby.txt"
-    result = ruby_exe(bad_embedded_ruby, options: '-x', args: '2>&1')
-    result.should include "no Ruby script found in input"
+    result = ruby_exe(bad_embedded_ruby, options: '-x', args: '2>&1', exit_status: 1)
+    result.should.include? "no Ruby script found in input"
   end
 
   it "behaves as -x was set when non-ruby shebang is encountered on first line" do
diff --git a/spec/ruby/command_line/error_message_spec.rb b/spec/ruby/command_line/error_message_spec.rb
index 5fee3ead44..157cb8969c 100644
--- a/spec/ruby/command_line/error_message_spec.rb
+++ b/spec/ruby/command_line/error_message_spec.rb
@@ -2,10 +2,15 @@ require_relative '../spec_helper'
 
 describe "The error message caused by an exception" do
   it "is not printed to stdout" do
-    out = ruby_exe("this_does_not_exist", args: "2> #{File::NULL}")
-    out.chomp.empty?.should == true
+    out = ruby_exe("this_does_not_exist", args: "2> #{File::NULL}", exit_status: 1)
+    out.chomp.should.empty?
 
-    out = ruby_exe("end #syntax error", args: "2> #{File::NULL}")
-    out.chomp.empty?.should == true
+    out = ruby_exe("end #syntax error", args: "2> #{File::NULL}", exit_status: 1)
+    out.chomp.should.empty?
+  end
+
+  it "is not modified with extra escaping of control characters and backslashes" do
+    out = ruby_exe('raise "\e[31mRed\e[0m error\\\\message"', args: "2>&1", exit_status: 1)
+    out.chomp.should.include?("\e[31mRed\e[0m error\\message")
   end
 end
diff --git a/spec/ruby/command_line/feature_spec.rb b/spec/ruby/command_line/feature_spec.rb
index 02571ee8c6..0a3252b88d 100644
--- a/spec/ruby/command_line/feature_spec.rb
+++ b/spec/ruby/command_line/feature_spec.rb
@@ -1,6 +1,12 @@
 require_relative '../spec_helper'
 
 describe "The --enable and --disable flags" do
+  before :all do
+    # Since some specs disable reading RUBYOPT, we instead pass its contents as :options for those specs
+    rubyopt = [ENV["RUBYOPT"]]
+    rubyopt << ENV["#{RUBY_ENGINE.upcase}OPT"] unless RUBY_ENGINE == 'ruby'
+    @rubyopt = RUBY_ENGINE == "ruby" ? "" : rubyopt.compact.join(" ")
+  end
 
   it "can be used with gems" do
     ruby_exe("p defined?(Gem)", options: "--enable=gems").chomp.should == "\"constant\""
@@ -25,9 +31,9 @@ describe "The --enable and --disable flags" do
 
   it "can be used with rubyopt" do
     ruby_exe("p $VERBOSE", options: "--enable=rubyopt", env: {'RUBYOPT' => '-w'}).chomp.should == "true"
-    ruby_exe("p $VERBOSE", options: "--disable=rubyopt", env: {'RUBYOPT' => '-w'}).chomp.should == "false"
+    ruby_exe("p $VERBOSE", options: "#{@rubyopt} --disable=rubyopt", env: {'RUBYOPT' => '-w'}).chomp.should == "false"
     ruby_exe("p $VERBOSE", options: "--enable-rubyopt", env: {'RUBYOPT' => '-w'}).chomp.should == "true"
-    ruby_exe("p $VERBOSE", options: "--disable-rubyopt", env: {'RUBYOPT' => '-w'}).chomp.should == "false"
+    ruby_exe("p $VERBOSE", options: "#{@rubyopt} --disable-rubyopt", env: {'RUBYOPT' => '-w'}).chomp.should == "false"
   end
 
   it "can be used with frozen-string-literal" do
@@ -37,20 +43,29 @@ describe "The --enable and --disable flags" do
     ruby_exe("p 'foo'.frozen?", options: "--disable-frozen-string-literal").chomp.should == "false"
   end
 
-  it "can be used with all" do
+  # frequently hangs for >60s on GitHub Actions macos-latest
+  # MinGW's YJIT support seems broken
+  platform_is_not :darwin, :mingw do
+    it "can be used with all for enable" do
+      e = "p [defined?(Gem), defined?(DidYouMean), $VERBOSE, 'foo'.frozen?]"
+      env = {'RUBYOPT' => '-w'}
+      # Use a single variant here because it can be quite slow as it might enable jit, etc
+      ruby_exe(e, options: "--enable-all", env: env).chomp.should == "[\"constant\", \"constant\", true, true]"
+    end unless defined?(RubyVM::YJIT) && defined?(RubyVM::ZJIT) && RubyVM::ZJIT.enabled? # You're not supposed to enable YJIT with --enable-all when ZJIT options are passed.
+  end
+
+  it "can be used with all for disable" do
     e = "p [defined?(Gem), defined?(DidYouMean), $VERBOSE, 'foo'.frozen?]"
     env = {'RUBYOPT' => '-w'}
-    ruby_exe(e, options: "--enable=all", env: env).chomp.should == "[\"constant\", \"constant\", true, true]"
-    ruby_exe(e, options: "--enable-all", env: env).chomp.should == "[\"constant\", \"constant\", true, true]"
-    ruby_exe(e, options: "--disable=all", env: env).chomp.should == "[nil, nil, false, false]"
-    ruby_exe(e, options: "--disable-all", env: env).chomp.should == "[nil, nil, false, false]"
+    ruby_exe(e, options: "#{@rubyopt} --disable=all", env: env).chomp.should == "[nil, nil, false, false]"
+    ruby_exe(e, options: "#{@rubyopt} --disable-all", env: env).chomp.should == "[nil, nil, false, false]"
   end
 
   it "prints a warning for unknown features" do
-    ruby_exe("p 14", options: "--enable=ruby-spec-feature-does-not-exist 2>&1").chomp.should include('warning: unknown argument for --enable')
-    ruby_exe("p 14", options: "--disable=ruby-spec-feature-does-not-exist 2>&1").chomp.should include('warning: unknown argument for --disable')
-    ruby_exe("p 14", options: "--enable-ruby-spec-feature-does-not-exist 2>&1").chomp.should include('warning: unknown argument for --enable')
-    ruby_exe("p 14", options: "--disable-ruby-spec-feature-does-not-exist 2>&1").chomp.should include('warning: unknown argument for --disable')
+    ruby_exe("p 14", options: "--enable=ruby-spec-feature-does-not-exist 2>&1").chomp.should.include?('warning: unknown argument for --enable')
+    ruby_exe("p 14", options: "--disable=ruby-spec-feature-does-not-exist 2>&1").chomp.should.include?('warning: unknown argument for --disable')
+    ruby_exe("p 14", options: "--enable-ruby-spec-feature-does-not-exist 2>&1").chomp.should.include?('warning: unknown argument for --enable')
+    ruby_exe("p 14", options: "--disable-ruby-spec-feature-does-not-exist 2>&1").chomp.should.include?('warning: unknown argument for --disable')
   end
 
 end
diff --git a/spec/ruby/command_line/fixtures/backtrace.rb b/spec/ruby/command_line/fixtures/backtrace.rb
new file mode 100644
index 0000000000..99acae95c8
--- /dev/null
+++ b/spec/ruby/command_line/fixtures/backtrace.rb
@@ -0,0 +1,35 @@
+def a
+  raise 'oops'
+end
+
+def b
+  a
+end
+
+def c
+  b
+end
+
+def d
+  c
+end
+
+arg = ARGV.first
+$stderr.puts arg
+
+case arg
+when 'full_message'
+  begin
+    d
+  rescue => exc
+    puts exc.full_message
+  end
+when 'backtrace'
+  begin
+    d
+  rescue => exc
+    puts exc.backtrace
+  end
+else
+  d
+end
diff --git a/spec/ruby/command_line/fixtures/bin/bad_embedded_ruby.txt b/spec/ruby/command_line/fixtures/bin/bad_embedded_ruby.txt
index a2b7ad085f..61b946977a 100644
--- a/spec/ruby/command_line/fixtures/bin/bad_embedded_ruby.txt
+++ b/spec/ruby/command_line/fixtures/bin/bad_embedded_ruby.txt
@@ -1,3 +1,3 @@
-@@@This line is not value Ruby
+@@@This line is not valid Ruby
 #!rub_y
 puts 'success'
diff --git a/spec/ruby/command_line/fixtures/bin/embedded_ruby.txt b/spec/ruby/command_line/fixtures/bin/embedded_ruby.txt
index c556bf0b71..0ec0f358db 100644
--- a/spec/ruby/command_line/fixtures/bin/embedded_ruby.txt
+++ b/spec/ruby/command_line/fixtures/bin/embedded_ruby.txt
@@ -1,3 +1,3 @@
-@@@This line is not value Ruby
+@@@This line is not valid Ruby
 #!ruby
-puts 'success'
\ No newline at end of file
+puts 'success'
diff --git a/spec/ruby/command_line/fixtures/bin/hybrid_launcher.sh b/spec/ruby/command_line/fixtures/bin/hybrid_launcher.sh
index 0eede2a99f..fd3249f0e5 100644
--- a/spec/ruby/command_line/fixtures/bin/hybrid_launcher.sh
+++ b/spec/ruby/command_line/fixtures/bin/hybrid_launcher.sh
@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
-exec somehow this file
+echo 'error' && exit 1
 #!ruby
 puts 'success'
diff --git a/spec/ruby/command_line/fixtures/debug_info.rb b/spec/ruby/command_line/fixtures/debug_info.rb
index ee607910c0..f02b041920 100644
--- a/spec/ruby/command_line/fixtures/debug_info.rb
+++ b/spec/ruby/command_line/fixtures/debug_info.rb
@@ -1,4 +1,3 @@
-# frozen_string_literal: true
 a = 'string'
 b = a
 c = b
diff --git a/spec/ruby/command_line/fixtures/freeze_flag_required_diff_enc.rb b/spec/ruby/command_line/fixtures/freeze_flag_required_diff_enc.rb
index fa348d59e7..df4b952c46 100644
--- a/spec/ruby/command_line/fixtures/freeze_flag_required_diff_enc.rb
+++ b/spec/ruby/command_line/fixtures/freeze_flag_required_diff_enc.rb
diff --git a/spec/ruby/command_line/fixtures/freeze_flag_two_literals.rb b/spec/ruby/command_line/fixtures/freeze_flag_two_literals.rb
index 074092c9d9..f5547a5bae 100644
--- a/spec/ruby/command_line/fixtures/freeze_flag_two_literals.rb
+++ b/spec/ruby/command_line/fixtures/freeze_flag_two_literals.rb
@@ -1 +1 @@
-p "abc".object_id == "abc".object_id
+p "abc".equal?("abc")
diff --git a/spec/ruby/command_line/fixtures/string_literal_frozen_comment.rb b/spec/ruby/command_line/fixtures/string_literal_frozen_comment.rb
new file mode 100644
index 0000000000..fb84b546c0
--- /dev/null
+++ b/spec/ruby/command_line/fixtures/string_literal_frozen_comment.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+frozen = "test".frozen?
+interned = "test".equal?("test")
+puts "frozen:#{frozen} interned:#{interned}"
diff --git a/spec/ruby/command_line/fixtures/string_literal_mutable_comment.rb b/spec/ruby/command_line/fixtures/string_literal_mutable_comment.rb
new file mode 100644
index 0000000000..381a742001
--- /dev/null
+++ b/spec/ruby/command_line/fixtures/string_literal_mutable_comment.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: false
+frozen = "test".frozen?
+interned = "test".equal?("test")
+puts "frozen:#{frozen} interned:#{interned}"
diff --git a/spec/ruby/command_line/fixtures/string_literal_raw.rb b/spec/ruby/command_line/fixtures/string_literal_raw.rb
new file mode 100644
index 0000000000..56b1841296
--- /dev/null
+++ b/spec/ruby/command_line/fixtures/string_literal_raw.rb
@@ -0,0 +1,3 @@
+frozen = "test".frozen?
+interned = "test".equal?("test")
+puts "frozen:#{frozen} interned:#{interned}"
diff --git a/spec/ruby/command_line/fixtures/test_file.rb b/spec/ruby/command_line/fixtures/test_file.rb
index 961e3c0b0c..30a832299e 100644
--- a/spec/ruby/command_line/fixtures/test_file.rb
+++ b/spec/ruby/command_line/fixtures/test_file.rb
@@ -1 +1 @@
-"test file"
+puts "REQUIRED"
diff --git a/spec/ruby/command_line/frozen_strings_spec.rb b/spec/ruby/command_line/frozen_strings_spec.rb
index 647b69daed..32ff7d0371 100644
--- a/spec/ruby/command_line/frozen_strings_spec.rb
+++ b/spec/ruby/command_line/frozen_strings_spec.rb
@@ -19,11 +19,76 @@ describe "The --enable-frozen-string-literal flag causes string literals to" do
   end
 end
 
+describe "The --disable-frozen-string-literal flag causes string literals to" do
+
+  it "produce a different object each time" do
+    ruby_exe(fixture(__FILE__, "freeze_flag_one_literal.rb"), options: "--disable-frozen-string-literal").chomp.should == "false"
+  end
+
+end
+
+describe "With neither --enable-frozen-string-literal nor --disable-frozen-string-literal flag set" do
+  before do
+    # disable --enable-frozen-string-literal and --disable-frozen-string-literal passed in $RUBYOPT
+    @rubyopt = ENV["RUBYOPT"]
+    ENV["RUBYOPT"] = ""
+  end
+
+  after do
+    ENV["RUBYOPT"] = @rubyopt
+  end
+
+  it "produce a different object each time" do
+    ruby_exe(fixture(__FILE__, "freeze_flag_one_literal.rb")).chomp.should == "false"
+  end
+
+  context "if file has no frozen_string_literal comment" do
+    it "produce different mutable strings each time" do
+      ruby_exe(fixture(__FILE__, "string_literal_raw.rb")).chomp.should == "frozen:false interned:false"
+    end
+
+    guard -> { ruby_version_is "3.4" and !"test".frozen? } do
+      it "complain about modification of produced mutable strings" do
+        -> { eval(<<~RUBY) }.should complain(/warning: literal string will be frozen in the future \(run with --debug-frozen-string-literal for more information\)/)
+          "test" << "!"
+        RUBY
+      end
+
+      it "does not complain about modification if Warning[:deprecated] is false" do
+        deprecated = Warning[:deprecated]
+        Warning[:deprecated] = false
+        -> { eval(<<~RUBY) }.should_not complain
+          "test" << "!"
+        RUBY
+      ensure
+        Warning[:deprecated] = deprecated
+      end
+    end
+  end
+
+  it "if file has frozen_string_literal:true comment produce same frozen strings each time" do
+    ruby_exe(fixture(__FILE__, "string_literal_frozen_comment.rb")).chomp.should == "frozen:true interned:true"
+  end
+
+  it "if file has frozen_string_literal:false comment produce different mutable strings each time" do
+    ruby_exe(fixture(__FILE__, "string_literal_mutable_comment.rb")).chomp.should == "frozen:false interned:false"
+  end
+end
+
 describe "The --debug flag produces" do
   it "debugging info on attempted frozen string modification" do
-    error_str = ruby_exe(fixture(__FILE__, 'debug_info.rb'), options: '--debug',  args: "2>&1")
-    error_str.should include("can't modify frozen String")
-    error_str.should include("created at")
-    error_str.should include("command_line/fixtures/debug_info.rb:2")
+    error_str = ruby_exe(fixture(__FILE__, 'debug_info.rb'), options: '--enable-frozen-string-literal --debug',  args: "2>&1")
+    error_str.should.include?("can't modify frozen String")
+    error_str.should.include?("created at")
+    error_str.should.include?("command_line/fixtures/debug_info.rb:1")
+  end
+
+  guard -> { ruby_version_is "3.4" and !"test".frozen? } do
+    it "debugging info on mutating chilled string" do
+      error_str = ruby_exe(fixture(__FILE__, 'debug_info.rb'), options: '-w --debug',  args: "2>&1")
+      error_str.should.include?("literal string will be frozen in the future")
+      error_str.should.include?("the string was created here")
+      error_str.should.include?("command_line/fixtures/debug_info.rb:1")
+    end
   end
 end
diff --git a/spec/ruby/command_line/rubylib_spec.rb b/spec/ruby/command_line/rubylib_spec.rb
index b45919b997..1bedd146e3 100644
--- a/spec/ruby/command_line/rubylib_spec.rb
+++ b/spec/ruby/command_line/rubylib_spec.rb
@@ -14,15 +14,15 @@ describe "The RUBYLIB environment variable" do
     dir = tmp("rubylib/incl")
     ENV["RUBYLIB"] = @pre + dir
     paths = ruby_exe("puts $LOAD_PATH").lines.map(&:chomp)
-    paths.should include(dir)
+    paths.should.include?(dir)
   end
 
   it "adds a File::PATH_SEPARATOR-separated list of directories to $LOAD_PATH" do
     dir1, dir2 = tmp("rubylib/incl1"), tmp("rubylib/incl2")
     ENV["RUBYLIB"] = @pre + "#{dir1}#{File::PATH_SEPARATOR}#{dir2}"
     paths = ruby_exe("puts $LOAD_PATH").lines.map(&:chomp)
-    paths.should include(dir1)
-    paths.should include(dir2)
+    paths.should.include?(dir1)
+    paths.should.include?(dir2)
     paths.index(dir1).should < paths.index(dir2)
   end
 
@@ -46,8 +46,8 @@ describe "The RUBYLIB environment variable" do
     rubylib_dir = tmp("rubylib_include")
     ENV["RUBYLIB"] = @pre + rubylib_dir
     paths = ruby_exe("puts $LOAD_PATH", options: "-I #{dash_i_dir}").lines.map(&:chomp)
-    paths.should include(dash_i_dir)
-    paths.should include(rubylib_dir)
+    paths.should.include?(dash_i_dir)
+    paths.should.include?(rubylib_dir)
     paths.index(dash_i_dir).should < paths.index(rubylib_dir)
   end
 
@@ -56,14 +56,14 @@ describe "The RUBYLIB environment variable" do
     rubylib_dir = tmp("rubylib_include")
     ENV["RUBYLIB"] = @pre + rubylib_dir
     paths = ruby_exe("puts $LOAD_PATH", env: { "RUBYOPT" => "-I#{rubyopt_dir}" }).lines.map(&:chomp)
-    paths.should include(rubyopt_dir)
-    paths.should include(rubylib_dir)
+    paths.should.include?(rubyopt_dir)
+    paths.should.include?(rubylib_dir)
     paths.index(rubyopt_dir).should < paths.index(rubylib_dir)
   end
 
   it "keeps spaces in the value" do
     ENV["RUBYLIB"] = @pre + " rubylib/incl "
     out = ruby_exe("puts $LOAD_PATH")
-    out.should include(" rubylib/incl ")
+    out.should.include?(" rubylib/incl ")
   end
 end
diff --git a/spec/ruby/command_line/rubyopt_spec.rb b/spec/ruby/command_line/rubyopt_spec.rb
index 2db42f77ef..eb297cd6fe 100644
--- a/spec/ruby/command_line/rubyopt_spec.rb
+++ b/spec/ruby/command_line/rubyopt_spec.rb
@@ -11,52 +11,70 @@ describe "Processing RUBYOPT" do
 
   it "adds the -I path to $LOAD_PATH" do
     ENV["RUBYOPT"] = "-Ioptrubyspecincl"
-    result = ruby_exe("puts $LOAD_PATH.grep(/byspecin/)", escape: true)
+    result = ruby_exe("puts $LOAD_PATH.grep(/byspecin/)")
     result.chomp[-15..-1].should == "optrubyspecincl"
   end
 
   it "sets $DEBUG to true for '-d'" do
     ENV["RUBYOPT"] = '-d'
     command = %[puts "value of $DEBUG is \#{$DEBUG}"]
-    result = ruby_exe(command, escape: true, args: "2>&1")
+    result = ruby_exe(command, args: "2>&1")
     result.should =~ /value of \$DEBUG is true/
   end
 
-  guard -> { not CROSS_COMPILING } do
+  guard -> { RbConfig::CONFIG["CROSS_COMPILING"] != "yes" } do
     it "prints the version number for '-v'" do
       ENV["RUBYOPT"] = '-v'
-      ruby_exe("")[/\A.*/].should == RUBY_DESCRIPTION
+      ruby_exe("")[/\A.*/].gsub(/\s\+(YJIT( \w+)?|ZJIT( \w+)?|PRISM|GC(\[\w+\])?)(?=\s)/, "").should == RUBY_DESCRIPTION.gsub(/\s\+(YJIT( \w+)?|ZJIT( \w+)?|PRISM|GC(\[\w+\])?)(?=\s)/, "")
     end
 
     it "ignores whitespace around the option" do
       ENV["RUBYOPT"] = ' -v '
-      ruby_exe("")[/\A.*/].should == RUBY_DESCRIPTION
+      ruby_exe("")[/\A.*/].gsub(/\s\+(YJIT( \w+)?|ZJIT( \w+)?|PRISM|GC(\[\w+\])?)(?=\s)/, "").should == RUBY_DESCRIPTION.gsub(/\s\+(YJIT( \w+)?|ZJIT( \w+)?|PRISM|GC(\[\w+\])?)(?=\s)/, "")
     end
   end
 
   it "sets $VERBOSE to true for '-w'" do
     ENV["RUBYOPT"] = '-w'
-    ruby_exe("p $VERBOSE", escape: true).chomp.should == "true"
+    ruby_exe("p $VERBOSE").chomp.should == "true"
   end
 
   it "sets $VERBOSE to true for '-W'" do
     ENV["RUBYOPT"] = '-W'
-    ruby_exe("p $VERBOSE", escape: true).chomp.should == "true"
+    ruby_exe("p $VERBOSE").chomp.should == "true"
   end
 
   it "sets $VERBOSE to nil for '-W0'" do
     ENV["RUBYOPT"] = '-W0'
-    ruby_exe("p $VERBOSE", escape: true).chomp.should == "nil"
+    ruby_exe("p $VERBOSE").chomp.should == "nil"
   end
 
   it "sets $VERBOSE to false for '-W1'" do
     ENV["RUBYOPT"] = '-W1'
-    ruby_exe("p $VERBOSE", escape: true).chomp.should == "false"
+    ruby_exe("p $VERBOSE").chomp.should == "false"
   end
 
   it "sets $VERBOSE to true for '-W2'" do
     ENV["RUBYOPT"] = '-W2'
-    ruby_exe("p $VERBOSE", escape: true).chomp.should == "true"
+    ruby_exe("p $VERBOSE").chomp.should == "true"
+  end
+
+  it "suppresses deprecation warnings for '-W:no-deprecated'" do
+    ENV["RUBYOPT"] = '-W:no-deprecated'
+    result = ruby_exe('$; = ""', args: '2>&1')
+    result.should == ""
+  end
+
+  it "suppresses experimental warnings for '-W:no-experimental'" do
+    ENV["RUBYOPT"] = '-W:no-experimental'
+    result = ruby_exe('case 0; in a; end', args: '2>&1')
+    result.should == ""
+  end
+
+  it "suppresses deprecation and experimental warnings for '-W:no-deprecated -W:no-experimental'" do
+    ENV["RUBYOPT"] = '-W:no-deprecated -W:no-experimental'
+    result = ruby_exe('case ($; = ""); in a; end', args: '2>&1')
+    result.should == ""
   end
 
   it "requires the file for '-r'" do
@@ -67,101 +85,101 @@ describe "Processing RUBYOPT" do
 
   it "raises a RuntimeError for '-a'" do
     ENV["RUBYOPT"] = '-a'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-p'" do
     ENV["RUBYOPT"] = '-p'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-n'" do
     ENV["RUBYOPT"] = '-n'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-y'" do
     ENV["RUBYOPT"] = '-y'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-c'" do
     ENV["RUBYOPT"] = '-c'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-s'" do
     ENV["RUBYOPT"] = '-s'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-h'" do
     ENV["RUBYOPT"] = '-h'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '--help'" do
     ENV["RUBYOPT"] = '--help'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-l'" do
     ENV["RUBYOPT"] = '-l'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-S'" do
     ENV["RUBYOPT"] = '-S irb'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-e'" do
     ENV["RUBYOPT"] = '-e0'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-i'" do
     ENV["RUBYOPT"] = '-i.bak'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-x'" do
     ENV["RUBYOPT"] = '-x'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-C'" do
     ENV["RUBYOPT"] = '-C'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-X'" do
     ENV["RUBYOPT"] = '-X.'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-F'" do
     ENV["RUBYOPT"] = '-F'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '-0'" do
     ENV["RUBYOPT"] = '-0'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '--copyright'" do
     ENV["RUBYOPT"] = '--copyright'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '--version'" do
     ENV["RUBYOPT"] = '--version'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 
   it "raises a RuntimeError for '--yydebug'" do
     ENV["RUBYOPT"] = '--yydebug'
-    ruby_exe("", args: '2>&1').should =~ /RuntimeError/
+    ruby_exe("", args: '2>&1', exit_status: 1).should =~ /RuntimeError/
   end
 end
diff --git a/spec/ruby/command_line/syntax_error_spec.rb b/spec/ruby/command_line/syntax_error_spec.rb
index f61cfe928d..88864c048e 100644
--- a/spec/ruby/command_line/syntax_error_spec.rb
+++ b/spec/ruby/command_line/syntax_error_spec.rb
@@ -2,12 +2,12 @@ require_relative '../spec_helper'
 
 describe "The interpreter" do
   it "prints an error when given a file with invalid syntax" do
-    out = ruby_exe(fixture(__FILE__, "bad_syntax.rb"), args: "2>&1")
-    out.should include "syntax error"
+    out = ruby_exe(fixture(__FILE__, "bad_syntax.rb"), args: "2>&1", exit_status: 1)
+    out.should.include?("SyntaxError")
   end
 
   it "prints an error when given code via -e with invalid syntax" do
-    out = ruby_exe(nil, args: "-e 'a{' 2>&1")
-    out.should include "syntax error"
+    out = ruby_exe(nil, args: "-e 'a{' 2>&1", exit_status: 1)
+    out.should.include?("SyntaxError")
   end
 end
diff --git a/spec/ruby/core/argf/argf_spec.rb b/spec/ruby/core/argf/argf_spec.rb
index af67170b98..f9468539bb 100644
--- a/spec/ruby/core/argf/argf_spec.rb
+++ b/spec/ruby/core/argf/argf_spec.rb
@@ -2,10 +2,10 @@ require_relative '../../spec_helper'
 
 describe "ARGF" do
   it "is extended by the Enumerable module" do
-    ARGF.should be_kind_of(Enumerable)
+    ARGF.should.is_a?(Enumerable)
   end
 
   it "is an instance of ARGF.class" do
-    ARGF.should be_an_instance_of(ARGF.class)
+    ARGF.should.instance_of?(ARGF.class)
   end
 end
diff --git a/spec/ruby/core/argf/argv_spec.rb b/spec/ruby/core/argf/argv_spec.rb
index eab03c450f..77dfe78c21 100644
--- a/spec/ruby/core/argf/argv_spec.rb
+++ b/spec/ruby/core/argf/argv_spec.rb
@@ -7,7 +7,7 @@ describe "ARGF.argv" do
   end
 
   it "returns ARGV for the initial ARGF" do
-    ARGF.argv.should equal ARGV
+    ARGF.argv.should.equal? ARGV
   end
 
   it "returns the remaining arguments to treat" do
diff --git a/spec/ruby/core/argf/binmode_spec.rb b/spec/ruby/core/argf/binmode_spec.rb
index bdcc6aa30a..5288e3199d 100644
--- a/spec/ruby/core/argf/binmode_spec.rb
+++ b/spec/ruby/core/argf/binmode_spec.rb
@@ -9,7 +9,7 @@ describe "ARGF.binmode" do
 
   it "returns self" do
     argf [@bin_file] do
-      @argf.binmode.should equal @argf
+      @argf.binmode.should.equal? @argf
     end
   end
 
@@ -34,7 +34,7 @@ describe "ARGF.binmode" do
   it "sets the file's encoding to BINARY" do
     argf [@bin_file, @file1] do
       @argf.binmode
-      @argf.binmode?.should == true
+      @argf.should.binmode?
       @argf.gets.encoding.should == Encoding::BINARY
       @argf.skip
       @argf.read.encoding.should == Encoding::BINARY
diff --git a/spec/ruby/core/argf/bytes_spec.rb b/spec/ruby/core/argf/bytes_spec.rb
deleted file mode 100644
index 71d07fabcb..0000000000
--- a/spec/ruby/core/argf/bytes_spec.rb
+++ /dev/null
@@ -1,6 +0,0 @@
-require_relative '../../spec_helper'
-require_relative 'shared/each_byte'
-
-describe "ARGF.bytes" do
-  it_behaves_like :argf_each_byte, :bytes
-end
diff --git a/spec/ruby/core/argf/chars_spec.rb b/spec/ruby/core/argf/chars_spec.rb
deleted file mode 100644
index ee79ea763b..0000000000
--- a/spec/ruby/core/argf/chars_spec.rb
+++ /dev/null
@@ -1,6 +0,0 @@
-require_relative '../../spec_helper'
-require_relative 'shared/each_char'
-
-describe "ARGF.chars" do
-  it_behaves_like :argf_each_char, :chars
-end
diff --git a/spec/ruby/core/argf/close_spec.rb b/spec/ruby/core/argf/close_spec.rb
index d4d6a51e72..8ca7d71dc2 100644
--- a/spec/ruby/core/argf/close_spec.rb
+++ b/spec/ruby/core/argf/close_spec.rb
@@ -10,20 +10,20 @@ describe "ARGF.close" do
     argf [@file1_name, @file2_name] do
       io = @argf.to_io
       @argf.close
-      io.closed?.should be_true
+      io.closed?.should == true
     end
   end
 
   it "returns self" do
     argf [@file1_name, @file2_name] do
-      @argf.close.should equal(@argf)
+      @argf.close.should.equal?(@argf)
     end
   end
 
   it "doesn't raise an IOError if called on a closed stream" do
     argf [@file1_name] do
-      -> { @argf.close }.should_not raise_error
-      -> { @argf.close }.should_not raise_error
+      -> { @argf.close }.should_not.raise
+      -> { @argf.close }.should_not.raise
     end
   end
 end
diff --git a/spec/ruby/core/argf/closed_spec.rb b/spec/ruby/core/argf/closed_spec.rb
index e2dd6134e5..769381e8c3 100644
--- a/spec/ruby/core/argf/closed_spec.rb
+++ b/spec/ruby/core/argf/closed_spec.rb
@@ -11,7 +11,7 @@ describe "ARGF.closed?" do
       stream = @argf.to_io
       stream.close
 
-      @argf.closed?.should be_true
+      @argf.closed?.should == true
       stream.reopen(@argf.filename, 'r')
     end
   end
diff --git a/spec/ruby/core/argf/codepoints_spec.rb b/spec/ruby/core/argf/codepoints_spec.rb
deleted file mode 100644
index 7aa8a761fe..0000000000
--- a/spec/ruby/core/argf/codepoints_spec.rb
+++ /dev/null
@@ -1,6 +0,0 @@
-require_relative '../../spec_helper'
-require_relative 'shared/each_codepoint'
-
-describe "ARGF.codepoints" do
-  it_behaves_like :argf_each_codepoint, :codepoints
-end
diff --git a/spec/ruby/core/argf/each_byte_spec.rb b/spec/ruby/core/argf/each_byte_spec.rb
index c5cce9f250..d9e4e7fe5b 100644
--- a/spec/ruby/core/argf/each_byte_spec.rb
+++ b/spec/ruby/core/argf/each_byte_spec.rb
@@ -1,6 +1,60 @@
 require_relative '../../spec_helper'
-require_relative 'shared/each_byte'
 
 describe "ARGF.each_byte" do
-  it_behaves_like :argf_each_byte, :each_byte
+  before :each do
+    @file1_name = fixture __FILE__, "file1.txt"
+    @file2_name = fixture __FILE__, "file2.txt"
+
+    @bytes = []
+    File.read(@file1_name).each_byte { |b| @bytes << b }
+    File.read(@file2_name).each_byte { |b| @bytes << b }
+  end
+
+  it "yields each byte of all streams to the passed block" do
+    argf [@file1_name, @file2_name] do
+      bytes = []
+      @argf.each_byte { |b| bytes << b }
+      bytes.should == @bytes
+    end
+  end
+
+  it "returns self when passed a block" do
+    argf [@file1_name, @file2_name] do
+      @argf.each_byte {}.should.equal?(@argf)
+    end
+  end
+
+  it "returns an Enumerator when passed no block" do
+    argf [@file1_name, @file2_name] do
+      enum = @argf.each_byte
+      enum.should.instance_of?(Enumerator)
+
+      bytes = []
+      enum.each { |b| bytes << b }
+      bytes.should == @bytes
+    end
+  end
+
+  describe "when no block is given" do
+    it "returns an Enumerator" do
+      argf [@file1_name, @file2_name] do
+        enum = @argf.each_byte
+        enum.should.instance_of?(Enumerator)
+
+        bytes = []
+        enum.each { |b| bytes << b }
+        bytes.should == @bytes
+      end
+    end
+
+    describe "returned Enumerator" do
+      describe "size" do
+        it "should return nil" do
+          argf [@file1_name, @file2_name] do
+            @argf.each_byte.size.should == nil
+          end
+        end
+      end
+    end
+  end
 end
diff --git a/spec/ruby/core/argf/each_char_spec.rb b/spec/ruby/core/argf/each_char_spec.rb
index 724e5e6e3e..62d19b6574 100644
--- a/spec/ruby/core/argf/each_char_spec.rb
+++ b/spec/ruby/core/argf/each_char_spec.rb
@@ -1,6 +1,60 @@
 require_relative '../../spec_helper'
-require_relative 'shared/each_char'
 
 describe "ARGF.each_char" do
-  it_behaves_like :argf_each_char, :each_char
+  before :each do
+    @file1_name = fixture __FILE__, "file1.txt"
+    @file2_name = fixture __FILE__, "file2.txt"
+
+    @chars = []
+    File.read(@file1_name).each_char { |c| @chars << c }
+    File.read(@file2_name).each_char { |c| @chars << c }
+  end
+
+  it "yields each char of all streams to the passed block" do
+    argf [@file1_name, @file2_name] do
+      chars = []
+      @argf.each_char { |c| chars << c }
+      chars.should == @chars
+    end
+  end
+
+  it "returns self when passed a block" do
+    argf [@file1_name, @file2_name] do
+      @argf.each_char {}.should.equal?(@argf)
+    end
+  end
+
+  it "returns an Enumerator when passed no block" do
+    argf [@file1_name, @file2_name] do
+      enum = @argf.each_char
+      enum.should.instance_of?(Enumerator)
+
+      chars = []
+      enum.each { |c| chars << c }
+      chars.should == @chars
+    end
+  end
+
+  describe "when no block is given" do
+    it "returns an Enumerator" do
+      argf [@file1_name, @file2_name] do
+        enum = @argf.each_char
+        enum.should.instance_of?(Enumerator)
+
+        chars = []
+        enum.each { |c| chars << c }
+        chars.should == @chars
+      end
+    end
+
+    describe "returned Enumerator" do
+      describe "size" do
+        it "should return nil" do
+          argf [@file1_name, @file2_name] do
+            @argf.each_char.size.should == nil
+          end
+        end
+      end
+    end
+  end
 end
diff --git a/spec/ruby/core/argf/each_codepoint_spec.rb b/spec/ruby/core/argf/each_codepoint_spec.rb
index 0bf8bf9764..ad55785cba 100644
--- a/spec/ruby/core/argf/each_codepoint_spec.rb
+++ b/spec/ruby/core/argf/each_codepoint_spec.rb
@@ -1,6 +1,60 @@
 require_relative '../../spec_helper'
-require_relative 'shared/each_codepoint'
 
 describe "ARGF.each_codepoint" do
-  it_behaves_like :argf_each_codepoint, :each_codepoint
+  before :each do
+    file1_name = fixture __FILE__, "file1.txt"
+    file2_name = fixture __FILE__, "file2.txt"
+    @filenames = [file1_name, file2_name]
+
+    @codepoints = File.read(file1_name).codepoints
+    @codepoints.concat File.read(file2_name).codepoints
+  end
+
+  it "is a public method" do
+    argf @filenames do
+      @argf.public_methods(false).should.include?(:each_codepoint)
+    end
+  end
+
+  it "does not require arguments" do
+    argf @filenames do
+      @argf.method(:each_codepoint).arity.should == 0
+    end
+  end
+
+  it "returns self when passed a block" do
+    argf @filenames do
+      @argf.each_codepoint {}.should.equal?(@argf)
+    end
+  end
+
+  it "returns an Enumerator when passed no block" do
+    argf @filenames do
+      @argf.each_codepoint.should.instance_of?(Enumerator)
+    end
+  end
+
+  it "yields each codepoint of all streams" do
+    argf @filenames do
+      @argf.each_codepoint.to_a.should == @codepoints
+    end
+  end
+
+  describe "when no block is given" do
+    it "returns an Enumerator" do
+      argf @filenames do
+        @argf.each_codepoint.should.instance_of?(Enumerator)
+      end
+    end
+
+    describe "returned Enumerator" do
+      describe "size" do
+        it "should return nil" do
+          argf @filenames do
+            @argf.each_codepoint.size.should == nil
+          end
+        end
+      end
+    end
+  end
 end
diff --git a/spec/ruby/core/argf/each_line_spec.rb b/spec/ruby/core/argf/each_line_spec.rb
index 52a7e5c411..fc4d6433b8 100644
--- a/spec/ruby/core/argf/each_line_spec.rb
+++ b/spec/ruby/core/argf/each_line_spec.rb
@@ -1,6 +1,64 @@
 require_relative '../../spec_helper'
-require_relative 'shared/each_line'
 
 describe "ARGF.each_line" do
-  it_behaves_like :argf_each_line, :each_line
+  before :each do
+    @file1_name = fixture __FILE__, "file1.txt"
+    @file2_name = fixture __FILE__, "file2.txt"
+
+    @lines  = File.readlines @file1_name
+    @lines += File.readlines @file2_name
+  end
+
+  it "is a public method" do
+    argf [@file1_name, @file2_name] do
+      @argf.public_methods(false).should.include?(:each_line)
+    end
+  end
+
+  it "requires multiple arguments" do
+    argf [@file1_name, @file2_name] do
+      @argf.method(:each_line).arity.should < 0
+    end
+  end
+
+  it "reads each line of files" do
+    argf [@file1_name, @file2_name] do
+      lines = []
+      @argf.each_line { |b| lines << b }
+      lines.should == @lines
+    end
+  end
+
+  it "returns self when passed a block" do
+    argf [@file1_name, @file2_name] do
+      @argf.each_line {}.should.equal?(@argf)
+    end
+  end
+
+  describe "with a separator" do
+    it "yields each separated section of all streams" do
+      argf [@file1_name, @file2_name] do
+        @argf.send(:each_line, '.').to_a.should ==
+          (File.readlines(@file1_name, '.') + File.readlines(@file2_name, '.'))
+      end
+    end
+  end
+
+  describe "when no block is given" do
+    it "returns an Enumerator" do
+      argf [@file1_name, @file2_name] do
+        @argf.each_line.should.instance_of?(Enumerator)
+      end
+    end
+
+    describe "returned Enumerator" do
+      describe "size" do
+        it "should return nil" do
+          argf [@file1_name, @file2_name] do
+            @argf.each_line.size.should == nil
+          end
+        end
+      end
+    end
+  end
 end
diff --git a/spec/ruby/core/argf/each_spec.rb b/spec/ruby/core/argf/each_spec.rb
index 5742ba43bd..25f60b31d2 100644
--- a/spec/ruby/core/argf/each_spec.rb
+++ b/spec/ruby/core/argf/each_spec.rb
@@ -1,6 +1,7 @@
 require_relative '../../spec_helper'
-require_relative 'shared/each_line'
 
 describe "ARGF.each" do
-  it_behaves_like :argf_each_line, :each
+  it "is an alias of ARGF.each_line" do
+    ARGF.method(:each).should == ARGF.method(:each_line)
+  end
 end
diff --git a/spec/ruby/core/argf/eof_spec.rb b/spec/ruby/core/argf/eof_spec.rb
index 518f6e566e..940d104d69 100644
--- a/spec/ruby/core/argf/eof_spec.rb
+++ b/spec/ruby/core/argf/eof_spec.rb
@@ -1,10 +1,32 @@
 require_relative '../../spec_helper'
-require_relative 'shared/eof'
 
 describe "ARGF.eof" do
-  it_behaves_like :argf_eof, :eof
+  it "is an alias of ARGF.eof?" do
+    ARGF.method(:eof).should == ARGF.method(:eof?)
+  end
 end
 
 describe "ARGF.eof?" do
-  it_behaves_like :argf_eof, :eof?
+  before :each do
+    @file1 = fixture __FILE__, "file1.txt"
+    @file2 = fixture __FILE__, "file2.txt"
+  end
+
+  # NOTE: this test assumes that fixtures files have two lines each
+  it "returns true when reaching the end of a file" do
+    argf [@file1, @file2] do
+      result = []
+      while @argf.gets
+        result << @argf.eof?
+      end
+      result.should == [false, true, false, true]
+    end
+  end
+
+  it "raises IOError when called on a closed stream" do
+    argf [@file1] do
+      @argf.read
+      -> { @argf.eof? }.should.raise(IOError)
+    end
+  end
 end
diff --git a/spec/ruby/core/argf/filename_spec.rb b/spec/ruby/core/argf/filename_spec.rb
index 7c0446269d..f4b6e922c6 100644
--- a/spec/ruby/core/argf/filename_spec.rb
+++ b/spec/ruby/core/argf/filename_spec.rb
@@ -1,6 +1,30 @@
 require_relative '../../spec_helper'
-require_relative 'shared/filename'
 
 describe "ARGF.filename" do
-  it_behaves_like :argf_filename, :filename
+  before :each do
+    @file1 = fixture __FILE__, "file1.txt"
+    @file2 = fixture __FILE__, "file2.txt"
+  end
+
+  # NOTE: this test assumes that fixtures files have two lines each
+  it "returns the current file name on each file" do
+    argf [@file1, @file2] do
+      result = []
+      # returns first current file even when not yet open
+      result << @argf.filename
+      result << @argf.filename while @argf.gets
+      # returns last current file even when closed
+      result << @argf.filename
+
+      result.map! { |f| File.expand_path(f) }
+      result.should == [@file1, @file1, @file1, @file2, @file2, @file2]
+    end
+  end
+
+  # NOTE: this test assumes that fixtures files have two lines each
+  it "sets the $FILENAME global variable with the current file name on each file" do
+    script = fixture __FILE__, "filename.rb"
+    out = ruby_exe(script, args: [@file1, @file2])
+    out.should == "#{@file1}\n#{@file1}\n#{@file2}\n#{@file2}\n#{@file2}\n"
+  end
 end
diff --git a/spec/ruby/core/argf/fileno_spec.rb b/spec/ruby/core/argf/fileno_spec.rb
index 29d50c3582..99245f043c 100644
--- a/spec/ruby/core/argf/fileno_spec.rb
+++ b/spec/ruby/core/argf/fileno_spec.rb
@@ -1,6 +1,26 @@
 require_relative '../../spec_helper'
-require_relative 'shared/fileno'
 
 describe "ARGF.fileno" do
-  it_behaves_like :argf_fileno, :fileno
+  before :each do
+    @file1 = fixture __FILE__, "file1.txt"
+    @file2 = fixture __FILE__, "file2.txt"
+  end
+
+  # NOTE: this test assumes that fixtures files have two lines each
+  it "returns the current file number on each file" do
+    argf [@file1, @file2] do
+      result = []
+      # returns first current file even when not yet open
+      result << @argf.fileno while @argf.gets
+      # returns last current file even when closed
+      result.map { |d| d.class }.should == [Integer, Integer, Integer, Integer]
+    end
+  end
+
+  it "raises an ArgumentError when called on a closed stream" do
+    argf [@file1] do
+      @argf.read
+      -> { @argf.fileno }.should.raise(ArgumentError)
+    end
+  end
 end
diff --git a/spec/ruby/core/argf/inspect_spec.rb b/spec/ruby/core/argf/inspect_spec.rb
new file mode 100644
index 0000000000..df0e3ba8dc
--- /dev/null
+++ b/spec/ruby/core/argf/inspect_spec.rb
@@ -0,0 +1,7 @@
+require_relative '../../spec_helper'
+
+describe "ARGF.inspect" do
+  it "is an alias of ARGF.to_s" do
+    ARGF.method(:inspect).should == ARGF.method(:to_s)
+  end
+end
diff --git a/spec/ruby/core/argf/lines_spec.rb b/spec/ruby/core/argf/lines_spec.rb
deleted file mode 100644
index 6ca6ff1256..0000000000
--- a/spec/ruby/core/argf/lines_spec.rb
+++ /dev/null
@@ -1,6 +0,0 @@
-require_relative '../../spec_helper'
-require_relative 'shared/each_line'
-
-describe "ARGF.lines" do
-  it_behaves_like :argf_each_line, :lines
-end
diff --git a/spec/ruby/core/argf/path_spec.rb b/spec/ruby/core/argf/path_spec.rb
index 7120f7d0e3..2f7b91999f 100644
--- a/spec/ruby/core/argf/path_spec.rb
+++ b/spec/ruby/core/argf/path_spec.rb
@@ -1,6 +1,7 @@
 require_relative '../../spec_helper'
-require_relative 'shared/filename'
 
 describe "ARGF.path" do
-  it_behaves_like :argf_filename, :path
+  it "is an alias of ARGF.filename" do
+    ARGF.method(:path).should == ARGF.method(:filename)
+  end
 end
diff --git a/spec/ruby/core/argf/pos_spec.rb b/spec/ruby/core/argf/pos_spec.rb
index fb3f25b945..1ff16e4f17 100644
--- a/spec/ruby/core/argf/pos_spec.rb
+++ b/spec/ruby/core/argf/pos_spec.rb
@@ -1,8 +1,35 @@
 require_relative '../../spec_helper'
-require_relative 'shared/pos'
 
 describe "ARGF.pos" do
-  it_behaves_like :argf_pos, :pos
+  before :each do
+    @file1 = fixture __FILE__, "file1.txt"
+    @file2 = fixture __FILE__, "file2.txt"
+  end
+
+  it "gives the correct position for each read operation" do
+    argf [@file1, @file2] do
+      size1 = File.size(@file1)
+      size2 = File.size(@file2)
+
+      @argf.read(2)
+      @argf.pos.should == 2
+      @argf.read(size1-2)
+      @argf.pos.should == size1
+      @argf.read(6)
+      @argf.pos.should == 6
+      @argf.rewind
+      @argf.pos.should == 0
+      @argf.read(size2)
+      @argf.pos.should == size2
+    end
+  end
+
+  it "raises an ArgumentError when called on a closed stream" do
+    argf [@file1] do
+      @argf.read
+      -> { @argf.pos }.should.raise(ArgumentError)
+    end
+  end
 end
 
 describe "ARGF.pos=" do
diff --git a/spec/ruby/core/argf/read_nonblock_spec.rb b/spec/ruby/core/argf/read_nonblock_spec.rb
index 804a459a62..5c6bd52d80 100644
--- a/spec/ruby/core/argf/read_nonblock_spec.rb
+++ b/spec/ruby/core/argf/read_nonblock_spec.rb
@@ -66,7 +66,7 @@ platform_is_not :windows do
         argf ['-'] do
           -> {
             @argf.read_nonblock(4)
-          }.should raise_error(IO::EAGAINWaitReadable)
+          }.should.raise(IO::EAGAINWaitReadable)
         end
       end
 
diff --git a/spec/ruby/core/argf/readchar_spec.rb b/spec/ruby/core/argf/readchar_spec.rb
index 4eca2efcf7..63632721ec 100644
--- a/spec/ruby/core/argf/readchar_spec.rb
+++ b/spec/ruby/core/argf/readchar_spec.rb
@@ -13,7 +13,7 @@ describe "ARGF.readchar" do
 
   it "raises EOFError when end of stream reached" do
     argf [@file1, @file2] do
-      -> { while @argf.readchar; end }.should raise_error(EOFError)
+      -> { while @argf.readchar; end }.should.raise(EOFError)
     end
   end
 end
diff --git a/spec/ruby/core/argf/readline_spec.rb b/spec/ruby/core/argf/readline_spec.rb
index db53c499e9..8c23549b1b 100644
--- a/spec/ruby/core/argf/readline_spec.rb
+++ b/spec/ruby/core/argf/readline_spec.rb
@@ -17,7 +17,7 @@ describe "ARGF.readline" do
 
   it "raises an EOFError when reaching end of files" do
     argf [@file1, @file2] do
-      -> { while @argf.readline; end }.should raise_error(EOFError)
+      -> { while @argf.readline; end }.should.raise(EOFError)
     end
   end
 end
diff --git a/spec/ruby/core/argf/readlines_spec.rb b/spec/ruby/core/argf/readlines_spec.rb
index 30be936dab..156bb6a33f 100644
--- a/spec/ruby/core/argf/readlines_spec.rb
+++ b/spec/ruby/core/argf/readlines_spec.rb
@@ -1,6 +1,24 @@
 require_relative '../../spec_helper'
-require_relative 'shared/readlines'
 
 describe "ARGF.readlines" do
-  it_behaves_like :argf_readlines, :readlines
+  before :each do
+    @file1 = fixture __FILE__, "file1.txt"
+    @file2 = fixture __FILE__, "file2.txt"
+
+    @lines  = File.readlines(@file1)
+    @lines += File.readlines(@file2)
+  end
+
+  it "reads all lines of all files" do
+    argf [@file1, @file2] do
+      @argf.readlines.should == @lines
+    end
+  end
+
+  it "returns an empty Array when end of stream reached" do
+    argf [@file1, @file2] do
+      @argf.read
+      @argf.readlines.should == []
+    end
+  end
 end
diff --git a/spec/ruby/core/argf/readpartial_spec.rb b/spec/ruby/core/argf/readpartial_spec.rb
index 5e284b3423..9f04e72cc2 100644
--- a/spec/ruby/core/argf/readpartial_spec.rb
+++ b/spec/ruby/core/argf/readpartial_spec.rb
@@ -16,7 +16,7 @@ describe "ARGF.readpartial" do
 
   it "raises an ArgumentError if called without a maximum read length" do
     argf [@file1_name] do
-      -> { @argf.readpartial }.should raise_error(ArgumentError)
+      -> { @argf.readpartial }.should.raise(ArgumentError)
     end
   end
 
@@ -29,7 +29,7 @@ describe "ARGF.readpartial" do
 
   it "clears output buffer even if EOFError is raised because @argf is at end" do
     begin
-      output = "to be cleared"
+      output = +"to be cleared"
 
       argf [@file1_name] do
         @argf.read
@@ -59,8 +59,8 @@ describe "ARGF.readpartial" do
       @argf.readpartial(@file1.size)
       @argf.readpartial(1)
       @argf.readpartial(@file2.size)
-      -> { @argf.readpartial(1) }.should raise_error(EOFError)
-      -> { @argf.readpartial(1) }.should raise_error(EOFError)
+      -> { @argf.readpartial(1) }.should.raise(EOFError)
+      -> { @argf.readpartial(1) }.should.raise(EOFError)
     end
   end
 
@@ -69,7 +69,7 @@ describe "ARGF.readpartial" do
       print ARGF.readpartial(#{@stdin.size})
       ARGF.readpartial(1) rescue print $!.class
     STR
-    stdin = ruby_exe(ruby_str, args: "< #{@stdin_name}", escape: true)
+    stdin = ruby_exe(ruby_str, args: "< #{@stdin_name}")
     stdin.should == @stdin + "EOFError"
   end
 end
diff --git a/spec/ruby/core/argf/rewind_spec.rb b/spec/ruby/core/argf/rewind_spec.rb
index b29f0b75b7..9255f790fe 100644
--- a/spec/ruby/core/argf/rewind_spec.rb
+++ b/spec/ruby/core/argf/rewind_spec.rb
@@ -33,7 +33,7 @@ describe "ARGF.rewind" do
   it "raises an ArgumentError when end of stream reached" do
     argf [@file1_name, @file2_name] do
       @argf.read
-      -> { @argf.rewind }.should raise_error(ArgumentError)
+      -> { @argf.rewind }.should.raise(ArgumentError)
     end
   end
 end
diff --git a/spec/ruby/core/argf/seek_spec.rb b/spec/ruby/core/argf/seek_spec.rb
index 2b73bd46fb..c1ea1ea438 100644
--- a/spec/ruby/core/argf/seek_spec.rb
+++ b/spec/ruby/core/argf/seek_spec.rb
@@ -57,7 +57,7 @@ describe "ARGF.seek" do
 
   it "takes at least one argument (offset)" do
     argf [@file1_name] do
-      -> { @argf.seek }.should raise_error(ArgumentError)
+      -> { @argf.seek }.should.raise(ArgumentError)
     end
   end
 end
diff --git a/spec/ruby/core/argf/shared/each_byte.rb b/spec/ruby/core/argf/shared/each_byte.rb
deleted file mode 100644
index 6b1dc1dae2..0000000000
--- a/spec/ruby/core/argf/shared/each_byte.rb
+++ /dev/null
@@ -1,58 +0,0 @@
-describe :argf_each_byte, shared: true do
-  before :each do
-    @file1_name = fixture __FILE__, "file1.txt"
-    @file2_name = fixture __FILE__, "file2.txt"
-
-    @bytes = []
-    File.read(@file1_name).each_byte { |b| @bytes << b }
-    File.read(@file2_name).each_byte { |b| @bytes << b }
-  end
-
-  it "yields each byte of all streams to the passed block" do
-    argf [@file1_name, @file2_name] do
-      bytes = []
-      @argf.send(@method) { |b| bytes << b }
-      bytes.should == @bytes
-    end
-  end
-
-  it "returns self when passed a block" do
-    argf [@file1_name, @file2_name] do
-      @argf.send(@method) {}.should equal(@argf)
-    end
-  end
-
-  it "returns an Enumerator when passed no block" do
-    argf [@file1_name, @file2_name] do
-      enum = @argf.send(@method)
-      enum.should be_an_instance_of(Enumerator)
-
-      bytes = []
-      enum.each { |b| bytes << b }
-      bytes.should == @bytes
-    end
-  end
-
-  describe "when no block is given" do
-    it "returns an Enumerator" do
-      argf [@file1_name, @file2_name] do
-        enum = @argf.send(@method)
-        enum.should be_an_instance_of(Enumerator)
-
-        bytes = []
-        enum.each { |b| bytes << b }
-        bytes.should == @bytes
-      end
-    end
-
-    describe "returned Enumerator" do
-      describe "size" do
-        it "should return nil" do
-          argf [@file1_name, @file2_name] do
-            @argf.send(@method).size.should == nil
-          end
-        end
-      end
-    end
-  end
-end
diff --git a/spec/ruby/core/argf/shared/each_char.rb b/spec/ruby/core/argf/shared/each_char.rb
deleted file mode 100644
index 9e333ecc5b..0000000000
--- a/spec/ruby/core/argf/shared/each_char.rb
+++ /dev/null
@@ -1,58 +0,0 @@
-describe :argf_each_char, shared: true do
-  before :each do
-    @file1_name = fixture __FILE__, "file1.txt"
-    @file2_name = fixture __FILE__, "file2.txt"
-
-    @chars = []
-    File.read(@file1_name).each_char { |c| @chars << c }
-    File.read(@file2_name).each_char { |c| @chars << c }
-  end
-
-  it "yields each char of all streams to the passed block" do
-    argf [@file1_name, @file2_name] do
-      chars = []
-      @argf.send(@method) { |c| chars << c }
-      chars.should == @chars
-    end
-  end
-
-  it "returns self when passed a block" do
-    argf [@file1_name, @file2_name] do
-      @argf.send(@method) {}.should equal(@argf)
-    end
-  end
-
-  it "returns an Enumerator when passed no block" do
-    argf [@file1_name, @file2_name] do
-      enum = @argf.send(@method)
-      enum.should be_an_instance_of(Enumerator)
-
-      chars = []
-      enum.each { |c| chars << c }
-      chars.should == @chars
-    end
-  end
-
-  describe "when no block is given" do
-    it "returns an Enumerator" do
-      argf [@file1_name, @file2_name] do
-        enum = @argf.send(@method)
-        enum.should be_an_instance_of(Enumerator)
-
-        chars = []
-        enum.each { |c| chars << c }
-        chars.should == @chars
-      end
-    end
-
-    describe "returned Enumerator" do
-      describe "size" do
-        it "should return nil" do
-          argf [@file1_name, @file2_name] do
-            @argf.send(@method).size.should == nil
-          end
-        end
-      end
-    end
-  end
-end
diff --git a/spec/ruby/core/argf/shared/each_codepoint.rb b/spec/ruby/core/argf/shared/each_codepoint.rb
deleted file mode 100644
index e2a2dfff46..0000000000
--- a/spec/ruby/core/argf/shared/each_codepoint.rb
+++ /dev/null
@@ -1,58 +0,0 @@
-describe :argf_each_codepoint, shared: true do
-  before :each do
-    file1_name = fixture __FILE__, "file1.txt"
-    file2_name = fixture __FILE__, "file2.txt"
-    @filenames = [file1_name, file2_name]
-
-    @codepoints = File.read(file1_name).codepoints
-    @codepoints.concat File.read(file2_name).codepoints
-  end
-
-  it "is a public method" do
-    argf @filenames do
-      @argf.public_methods(false).should include(@method)
-    end
-  end
-
-  it "does not require arguments" do
-    argf @filenames do
-      @argf.method(@method).arity.should == 0
-    end
-  end
-
-  it "returns self when passed a block" do
-    argf @filenames do
-      @argf.send(@method) {}.should equal(@argf)
-    end
-  end
-
-  it "returns an Enumerator when passed no block" do
-    argf @filenames do
-      @argf.send(@method).should be_an_instance_of(Enumerator)
-    end
-  end
-
-  it "yields each codepoint of all streams" do
-    argf @filenames do
-      @argf.send(@method).to_a.should == @codepoints
-    end
-  end
-
-  describe "when no block is given" do
-    it "returns an Enumerator" do
-      argf @filenames do
-        @argf.send(@method).should be_an_instance_of(Enumerator)
-      end
-    end
-
-    describe "returned Enumerator" do
-      describe "size" do
-        it "should return nil" do
-          argf @filenames do
-            @argf.send(@method).size.should == nil
-          end
-        end
-      end
-    end
-  end
-end
diff --git a/spec/ruby/core/argf/shared/each_line.rb b/spec/ruby/core/argf/shared/each_line.rb
deleted file mode 100644
index c0ef77dc54..0000000000
--- a/spec/ruby/core/argf/shared/each_line.rb
+++ /dev/null
@@ -1,62 +0,0 @@
-describe :argf_each_line, shared: true do
-  before :each do
-    @file1_name = fixture __FILE__, "file1.txt"
-    @file2_name = fixture __FILE__, "file2.txt"
-
-    @lines  = File.readlines @file1_name
-    @lines += File.readlines @file2_name
-  end
-
-  it "is a public method" do
-    argf [@file1_name, @file2_name] do
-      @argf.public_methods(false).should include(@method)
-    end
-  end
-
-  it "requires multiple arguments" do
-    argf [@file1_name, @file2_name] do
-      @argf.method(@method).arity.should < 0
-    end
-  end
-
-  it "reads each line of files" do
-    argf [@file1_name, @file2_name] do
-      lines = []
-      @argf.send(@method) { |b| lines << b }
-      lines.should == @lines
-    end
-  end
-
-  it "returns self when passed a block" do
-    argf [@file1_name, @file2_name] do
-      @argf.send(@method) {}.should equal(@argf)
-    end
-  end
-
-  describe "with a separator" do
-    it "yields each separated section of all streams" do
-      argf [@file1_name, @file2_name] do
-        @argf.send(@method, '.').to_a.should ==
-          (File.readlines(@file1_name, '.') + File.readlines(@file2_name, '.'))
-      end
-    end
-  end
-
-  describe "when no block is given" do
-    it "returns an Enumerator" do
-      argf [@file1_name, @file2_name] do
-        @argf.send(@method).should be_an_instance_of(Enumerator)
-      end
-    end
-
-    describe "returned Enumerator" do
-      describe "size" do
-        it "should return nil" do
-          argf [@file1_name, @file2_name] do
-            @argf.send(@method).size.should == nil
-          end
-        end
-      end
-    end
-  end
-end
diff --git a/spec/ruby/core/argf/shared/eof.rb b/spec/ruby/core/argf/shared/eof.rb
deleted file mode 100644
index 0e684f943f..0000000000
--- a/spec/ruby/core/argf/shared/eof.rb
+++ /dev/null
@@ -1,24 +0,0 @@
-describe :argf_eof, shared: true do
-  before :each do
-    @file1 = fixture __FILE__, "file1.txt"
-    @file2 = fixture __FILE__, "file2.txt"
-  end
-
-  # NOTE: this test assumes that fixtures files have two lines each
-  it "returns true when reaching the end of a file" do
-    argf [@file1, @file2] do
-      result = []
-      while @argf.gets
-        result << @argf.send(@method)
-      end
-      result.should == [false, true, false, true]
-    end
-  end
-
-  it "raises IOError when called on a closed stream" do
-    argf [@file1] do
-      @argf.read
-      -> { @argf.send(@method) }.should raise_error(IOError)
-    end
-  end
-end
diff --git a/spec/ruby/core/argf/shared/filename.rb b/spec/ruby/core/argf/shared/filename.rb
deleted file mode 100644
index f47c673dc0..0000000000
--- a/spec/ruby/core/argf/shared/filename.rb
+++ /dev/null
@@ -1,28 +0,0 @@
-describe :argf_filename, shared: true do
-  before :each do
-    @file1 = fixture __FILE__, "file1.txt"
-    @file2 = fixture __FILE__, "file2.txt"
-  end
-
-  # NOTE: this test assumes that fixtures files have two lines each
-  it "returns the current file name on each file" do
-    argf [@file1, @file2] do
-      result = []
-      # returns first current file even when not yet open
-      result << @argf.send(@method)
-      result << @argf.send(@method) while @argf.gets
-      # returns last current file even when closed
-      result << @argf.send(@method)
-
-      result.map! { |f| File.expand_path(f) }
-      result.should == [@file1, @file1, @file1, @file2, @file2, @file2]
-    end
-  end
-
-  # NOTE: this test assumes that fixtures files have two lines each
-  it "sets the $FILENAME global variable with the current file name on each file" do
-    script = fixture __FILE__, "filename.rb"
-    out = ruby_exe(script, args: [@file1, @file2])
-    out.should == "#{@file1}\n#{@file1}\n#{@file2}\n#{@file2}\n#{@file2}\n"
-  end
-end
diff --git a/spec/ruby/core/argf/shared/fileno.rb b/spec/ruby/core/argf/shared/fileno.rb
deleted file mode 100644
index 5d674048e2..0000000000
--- a/spec/ruby/core/argf/shared/fileno.rb
+++ /dev/null
@@ -1,24 +0,0 @@
-describe :argf_fileno, shared: true do
-  before :each do
-    @file1 = fixture __FILE__, "file1.txt"
-    @file2 = fixture __FILE__, "file2.txt"
-  end
-
-  # NOTE: this test assumes that fixtures files have two lines each
-  it "returns the current file number on each file" do
-    argf [@file1, @file2] do
-      result = []
-      # returns first current file even when not yet open
-      result << @argf.send(@method) while @argf.gets
-      # returns last current file even when closed
-      result.map { |d| d.class }.should == [Fixnum, Fixnum, Fixnum, Fixnum]
-    end
-  end
-
-  it "raises an ArgumentError when called on a closed stream" do
-    argf [@file1] do
-      @argf.read
-      -> { @argf.send(@method) }.should raise_error(ArgumentError)
-    end
-  end
-end
diff --git a/spec/ruby/core/argf/shared/getc.rb b/spec/ruby/core/argf/shared/getc.rb
index 8be39c60b6..d63372d9d7 100644
--- a/spec/ruby/core/argf/shared/getc.rb
+++ b/spec/ruby/core/argf/shared/getc.rb
@@ -9,7 +9,7 @@ describe :argf_getc, shared: true do
 
   it "reads each char of files" do
     argf [@file1, @file2] do
-      chars = ""
+      chars = +""
       @chars.size.times { chars << @argf.send(@method) }
       chars.should == @chars
     end
diff --git a/spec/ruby/core/argf/shared/pos.rb b/spec/ruby/core/argf/shared/pos.rb
deleted file mode 100644
index 9836d5f1e4..0000000000
--- a/spec/ruby/core/argf/shared/pos.rb
+++ /dev/null
@@ -1,31 +0,0 @@
-describe :argf_pos, shared: true do
-  before :each do
-    @file1 = fixture __FILE__, "file1.txt"
-    @file2 = fixture __FILE__, "file2.txt"
-  end
-
-  it "gives the correct position for each read operation" do
-    argf [@file1, @file2] do
-      size1 = File.size(@file1)
-      size2 = File.size(@file2)
-
-      @argf.read(2)
-      @argf.send(@method).should == 2
-      @argf.read(size1-2)
-      @argf.send(@method).should == size1
-      @argf.read(6)
-      @argf.send(@method).should == 6
-      @argf.rewind
-      @argf.send(@method).should == 0
-      @argf.read(size2)
-      @argf.send(@method).should == size2
-    end
-  end
-
-  it "raises an ArgumentError when called on a closed stream" do
-    argf [@file1] do
-      @argf.read
-      -> { @argf.send(@method) }.should raise_error(ArgumentError)
-    end
-  end
-end
diff --git a/spec/ruby/core/argf/shared/read.rb b/spec/ruby/core/argf/shared/read.rb
index fe903983c0..e76d022139 100644
--- a/spec/ruby/core/argf/shared/read.rb
+++ b/spec/ruby/core/argf/shared/read.rb
@@ -15,7 +15,7 @@ describe :argf_read, shared: true do
 
   it "treats second argument as an output buffer" do
     argf [@file1_name] do
-      buffer = ""
+      buffer = +""
       @argf.send(@method, @file1.size, buffer)
       buffer.should == @file1
     end
@@ -23,7 +23,7 @@ describe :argf_read, shared: true do
 
   it "clears output buffer before appending to it" do
     argf [@file1_name] do
-      buffer = "to be cleared"
+      buffer = +"to be cleared"
       @argf.send(@method, @file1.size, buffer)
       buffer.should == @file1
     end
diff --git a/spec/ruby/core/argf/shared/readlines.rb b/spec/ruby/core/argf/shared/readlines.rb
deleted file mode 100644
index 505fa94acb..0000000000
--- a/spec/ruby/core/argf/shared/readlines.rb
+++ /dev/null
@@ -1,22 +0,0 @@
-describe :argf_readlines, shared: true do
-  before :each do
-    @file1 = fixture __FILE__, "file1.txt"
-    @file2 = fixture __FILE__, "file2.txt"
-
-    @lines  = File.readlines(@file1)
-    @lines += File.readlines(@file2)
-  end
-
-  it "reads all lines of all files" do
-    argf [@file1, @file2] do
-      @argf.send(@method).should == @lines
-    end
-  end
-
-  it "returns an empty Array when end of stream reached" do
-    argf [@file1, @file2] do
-      @argf.read
-      @argf.send(@method).should == []
-    end
-  end
-end
diff --git a/spec/ruby/core/argf/skip_spec.rb b/spec/ruby/core/argf/skip_spec.rb
index 0181801c2d..bb1c0ae110 100644
--- a/spec/ruby/core/argf/skip_spec.rb
+++ b/spec/ruby/core/argf/skip_spec.rb
@@ -37,6 +37,6 @@ describe "ARGF.skip" do
   # which as a side-effect calls argf.file which will initialize
   # internals of ARGF enough for this to work.
   it "has no effect when nothing has been processed yet" do
-    -> { ARGF.class.new(@file1_name).skip }.should_not raise_error
+    -> { ARGF.class.new(@file1_name).skip }.should_not.raise
   end
 end
diff --git a/spec/ruby/core/argf/tell_spec.rb b/spec/ruby/core/argf/tell_spec.rb
index 16d9f29920..bb28df74a2 100644
--- a/spec/ruby/core/argf/tell_spec.rb
+++ b/spec/ruby/core/argf/tell_spec.rb
@@ -1,6 +1,7 @@
 require_relative '../../spec_helper'
-require_relative 'shared/pos'
 
 describe "ARGF.tell" do
-  it_behaves_like :argf_pos, :tell
+  it "is an alias of ARGF.pos" do
+    ARGF.method(:tell).should == ARGF.method(:pos)
+  end
 end
diff --git a/spec/ruby/core/argf/to_a_spec.rb b/spec/ruby/core/argf/to_a_spec.rb
index b17a93db33..d95dc732ec 100644
--- a/spec/ruby/core/argf/to_a_spec.rb
+++ b/spec/ruby/core/argf/to_a_spec.rb
@@ -1,6 +1,7 @@
 require_relative '../../spec_helper'
-require_relative 'shared/readlines'
 
 describe "ARGF.to_a" do
-  it_behaves_like :argf_readlines, :to_a
+  it "is an alias of ARGF.readlines" do
+    ARGF.method(:to_a).should == ARGF.method(:readlines)
+  end
 end
diff --git a/spec/ruby/core/argf/to_i_spec.rb b/spec/ruby/core/argf/to_i_spec.rb
index 2183de6cd4..e8df378f4e 100644
--- a/spec/ruby/core/argf/to_i_spec.rb
+++ b/spec/ruby/core/argf/to_i_spec.rb
@@ -1,6 +1,7 @@
 require_relative '../../spec_helper'
-require_relative 'shared/fileno'
 
 describe "ARGF.to_i" do
-  it_behaves_like :argf_fileno, :to_i
+  it "is an alias of ARGF.fileno" do
+    ARGF.method(:to_i).should == ARGF.method(:fileno)
+  end
 end
diff --git a/spec/ruby/core/argf/to_io_spec.rb b/spec/ruby/core/argf/to_io_spec.rb
index 062383d291..ab5de58bcf 100644
--- a/spec/ruby/core/argf/to_io_spec.rb
+++ b/spec/ruby/core/argf/to_io_spec.rb
@@ -15,7 +15,7 @@ describe "ARGF.to_io" do
         result << @argf.to_io
       end
 
-      result.each { |io| io.should be_kind_of(IO) }
+      result.each { |io| io.should.is_a?(IO) }
       result[0].should == result[1]
       result[2].should == result[3]
     end
diff --git a/spec/ruby/core/array/all_spec.rb b/spec/ruby/core/array/all_spec.rb
new file mode 100644
index 0000000000..680e8c26fa
--- /dev/null
+++ b/spec/ruby/core/array/all_spec.rb
@@ -0,0 +1,13 @@
+require_relative '../../spec_helper'
+require_relative 'shared/iterable_and_tolerating_size_increasing'
+
+describe "Array#all?" do
+  @value_to_return = -> _ { true }
+  it_behaves_like :array_iterable_and_tolerating_size_increasing, :all?
+
+  it "ignores the block if there is an argument" do
+    -> {
+      ['bar', 'foobar'].all?(/bar/) { false }.should == true
+    }.should complain(/given block not used/)
+  end
+end
diff --git a/spec/ruby/core/array/allocate_spec.rb b/spec/ruby/core/array/allocate_spec.rb
index 04f7c0d0ad..c9eceef590 100644
--- a/spec/ruby/core/array/allocate_spec.rb
+++ b/spec/ruby/core/array/allocate_spec.rb
@@ -3,7 +3,7 @@ require_relative '../../spec_helper'
 describe "Array.allocate" do
   it "returns an instance of Array" do
     ary = Array.allocate
-    ary.should be_an_instance_of(Array)
+    ary.should.instance_of?(Array)
   end
 
   it "returns a fully-formed instance of Array" do
@@ -14,6 +14,6 @@ describe "Array.allocate" do
   end
 
   it "does not accept any arguments" do
-    -> { Array.allocate(1) }.should raise_error(ArgumentError)
+    -> { Array.allocate(1) }.should.raise(ArgumentError)
   end
 end
diff --git a/spec/ruby/core/array/any_spec.rb b/spec/ruby/core/array/any_spec.rb
index 2fa5353e99..b51ce62f0f 100644
--- a/spec/ruby/core/array/any_spec.rb
+++ b/spec/ruby/core/array/any_spec.rb
@@ -1,24 +1,28 @@
 require_relative '../../spec_helper'
+require_relative 'shared/iterable_and_tolerating_size_increasing'
 
 describe "Array#any?" do
   describe 'with no block given (a default block of { |x| x } is implicit)' do
     it "is false if the array is empty" do
       empty_array = []
-      empty_array.any?.should == false
+      empty_array.should_not.any?
     end
 
     it "is false if the array is not empty, but all the members of the array are falsy" do
       falsy_array = [false, nil, false]
-      falsy_array.any?.should == false
+      falsy_array.should_not.any?
     end
 
     it "is true if the array has any truthy members" do
       not_empty_array = ['anything', nil]
-      not_empty_array.any?.should == true
+      not_empty_array.should.any?
     end
   end
 
   describe 'with a block given' do
+    @value_to_return = -> _ { false }
+    it_behaves_like :array_iterable_and_tolerating_size_increasing, :any?
+
     it 'is false if the array is empty' do
       empty_array = []
       empty_array.any? {|v| 1 == 1 }.should == false
@@ -34,4 +38,12 @@ describe "Array#any?" do
       array_with_members.any? {|v| v == 42 }.should == false
     end
   end
+
+  describe 'when given a pattern argument' do
+    it "ignores the block if there is an argument" do
+      -> {
+        ['bar', 'foobar'].any?(/bar/) { false }.should == true
+      }.should complain(/given block not used/)
+    end
+  end
 end
diff --git a/spec/ruby/core/array/append_spec.rb b/spec/ruby/core/array/append_spec.rb
index 302dc4a901..5480d9f65e 100644
--- a/spec/ruby/core/array/append_spec.rb
+++ b/spec/ruby/core/array/append_spec.rb
@@ -1,6 +1,5 @@
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
-require_relative 'shared/push'
 
 describe "Array#<<" do
   it "pushes the object onto the end of the array" do
@@ -10,8 +9,8 @@ describe "Array#<<" do
   it "returns self to allow chaining" do
     a = []
     b = a
-    (a << 1).should equal(b)
-    (a << 2 << 3).should equal(b)
+    (a << 1).should.equal?(b)
+    (a << 2 << 3).should.equal?(b)
   end
 
   it "correctly resizes the Array" do
@@ -30,13 +29,13 @@ describe "Array#<<" do
     a.should == [:foo]
   end
 
-  it "raises a #{frozen_error_class} on a frozen array" do
-    -> { ArraySpecs.frozen_array << 5 }.should raise_error(frozen_error_class)
+  it "raises a FrozenError on a frozen array" do
+    -> { ArraySpecs.frozen_array << 5 }.should.raise(FrozenError)
   end
 end
 
-ruby_version_is "2.5" do
-  describe "Array#append" do
-    it_behaves_like :array_push, :append
+describe "Array#append" do
+  it "is an alias of Array#push" do
+    Array.instance_method(:append).should == Array.instance_method(:push)
   end
 end
diff --git a/spec/ruby/core/array/assoc_spec.rb b/spec/ruby/core/array/assoc_spec.rb
index f8479d763c..a5026cf5d4 100644
--- a/spec/ruby/core/array/assoc_spec.rb
+++ b/spec/ruby/core/array/assoc_spec.rb
@@ -6,18 +6,18 @@ describe "Array#assoc" do
     s1 = ["colors", "red", "blue", "green"]
     s2 = [:letters, "a", "b", "c"]
     s3 = [4]
-    s4 = ["colors", "cyan", "yellow", "magenda"]
+    s4 = ["colors", "cyan", "yellow", "magenta"]
     s5 = [:letters, "a", "i", "u"]
     s_nil = [nil, nil]
     a = [s1, s2, s3, s4, s5, s_nil]
-    a.assoc(s1.first).should equal(s1)
-    a.assoc(s2.first).should equal(s2)
-    a.assoc(s3.first).should equal(s3)
-    a.assoc(s4.first).should equal(s1)
-    a.assoc(s5.first).should equal(s2)
-    a.assoc(s_nil.first).should equal(s_nil)
-    a.assoc(4).should equal(s3)
-    a.assoc("key not in array").should be_nil
+    a.assoc(s1.first).should.equal?(s1)
+    a.assoc(s2.first).should.equal?(s2)
+    a.assoc(s3.first).should.equal?(s3)
+    a.assoc(s4.first).should.equal?(s1)
+    a.assoc(s5.first).should.equal?(s2)
+    a.assoc(s_nil.first).should.equal?(s_nil)
+    a.assoc(4).should.equal?(s3)
+    a.assoc("key not in array").should == nil
   end
 
   it "calls == on first element of each array" do
@@ -25,16 +25,28 @@ describe "Array#assoc" do
     key2 = mock('key2')
     items = [['not it', 1], [ArraySpecs::AssocKey.new, 2], ['na', 3]]
 
-    items.assoc(key1).should equal(items[1])
-    items.assoc(key2).should be_nil
+    items.assoc(key1).should.equal?(items[1])
+    items.assoc(key2).should == nil
   end
 
   it "ignores any non-Array elements" do
-    [1, 2, 3].assoc(2).should be_nil
+    [1, 2, 3].assoc(2).should == nil
     s1 = [4]
     s2 = [5, 4, 3]
     a = ["foo", [], s1, s2, nil, []]
-    a.assoc(s1.first).should equal(s1)
-    a.assoc(s2.first).should equal(s2)
+    a.assoc(s1.first).should.equal?(s1)
+    a.assoc(s2.first).should.equal?(s2)
+  end
+
+  it "calls to_ary on non-array elements" do
+    s1 = [1, 2]
+    s2 = ArraySpecs::ArrayConvertible.new(2, 3)
+    a = [s1, s2]
+
+    s1.should_not_receive(:to_ary)
+    a.assoc(s1.first).should.equal?(s1)
+
+    a.assoc(2).should == [2, 3]
+    s2.called.should.equal?(:to_ary)
   end
 end
diff --git a/spec/ruby/core/array/at_spec.rb b/spec/ruby/core/array/at_spec.rb
index 8bc789fef7..3c7c99fdff 100644
--- a/spec/ruby/core/array/at_spec.rb
+++ b/spec/ruby/core/array/at_spec.rb
@@ -47,10 +47,10 @@ describe "Array#at" do
   end
 
   it "raises a TypeError when the passed argument can't be coerced to Integer" do
-    -> { [].at("cat") }.should raise_error(TypeError)
+    -> { [].at("cat") }.should.raise(TypeError)
   end
 
   it "raises an ArgumentError when 2 or more arguments are passed" do
-    -> { [:a, :b].at(0,1) }.should raise_error(ArgumentError)
+    -> { [:a, :b].at(0,1) }.should.raise(ArgumentError)
   end
 end
diff --git a/spec/ruby/core/array/bsearch_index_spec.rb b/spec/ruby/core/array/bsearch_index_spec.rb
index aafded178d..e1d5eb66bb 100644
--- a/spec/ruby/core/array/bsearch_index_spec.rb
+++ b/spec/ruby/core/array/bsearch_index_spec.rb
@@ -8,11 +8,11 @@ describe "Array#bsearch_index" do
     end
 
     it "returns an Enumerator" do
-      @enum.should be_an_instance_of(Enumerator)
+      @enum.should.instance_of?(Enumerator)
     end
 
     it "returns an Enumerator with unknown size" do
-      @enum.size.should be_nil
+      @enum.size.should == nil
     end
 
     it "returns index of element when block condition is satisfied" do
@@ -21,11 +21,11 @@ describe "Array#bsearch_index" do
   end
 
   it "raises a TypeError when block returns a String" do
-    -> { [1, 2, 3].bsearch_index { "not ok" } }.should raise_error(TypeError)
+    -> { [1, 2, 3].bsearch_index { "not ok" } }.should.raise(TypeError)
   end
 
   it "returns nil when block is empty" do
-    [1, 2, 3].bsearch_index {}.should be_nil
+    [1, 2, 3].bsearch_index {}.should == nil
   end
 
   context "minimum mode" do
@@ -40,8 +40,8 @@ describe "Array#bsearch_index" do
     end
 
     it "returns nil when block condition is never satisfied" do
-      @array.bsearch_index { false }.should be_nil
-      @array.bsearch_index { |x| x >= 100 }.should be_nil
+      @array.bsearch_index { false }.should == nil
+      @array.bsearch_index { |x| x >= 100 }.should == nil
     end
   end
 
@@ -51,34 +51,30 @@ describe "Array#bsearch_index" do
     end
 
     it "returns the index of any matched elements where element is between 4 <= x < 8" do
-      [1, 2].should include(@array.bsearch_index { |x| 1 - x / 4 })
+      [1, 2].should.include?(@array.bsearch_index { |x| 1 - x / 4 })
     end
 
     it "returns the index of any matched elements where element is between 8 <= x < 10" do
-      @array.bsearch_index { |x| 4 - x / 2 }.should be_nil
+      @array.bsearch_index { |x| 4 - x / 2 }.should == nil
     end
 
     it "returns nil when block never returns 0" do
-      @array.bsearch_index { |x| 1 }.should be_nil
-      @array.bsearch_index { |x| -1 }.should be_nil
-    end
-
-    it "returns the middle element when block always returns zero" do
-      @array.bsearch_index { |x| 0 }.should == 2
+      @array.bsearch_index { |x| 1 }.should == nil
+      @array.bsearch_index { |x| -1 }.should == nil
     end
 
     context "magnitude does not effect the result" do
       it "returns the index of any matched elements where element is between 4n <= xn < 8n" do
-        [1, 2].should include(@array.bsearch_index { |x| (1 - x / 4) * (2**100) })
+        [1, 2].should.include?(@array.bsearch_index { |x| (1 - x / 4) * (2**100) })
       end
 
       it "returns nil when block never returns 0" do
-        @array.bsearch_index { |x| 1 * (2**100) }.should be_nil
-        @array.bsearch_index { |x| (-1) * (2**100) }.should be_nil
+        @array.bsearch_index { |x| 1 * (2**100) }.should == nil
+        @array.bsearch_index { |x| (-1) * (2**100) }.should == nil
       end
 
-      it "handles values from Bignum#coerce" do
-        [1, 2].should include(@array.bsearch_index { |x| (2**100).coerce((1 - x / 4) * (2**100)).first })
+      it "handles values from Integer#coerce" do
+        [1, 2].should.include?(@array.bsearch_index { |x| (2**100).coerce((1 - x / 4) * (2**100)).first })
       end
     end
   end
diff --git a/spec/ruby/core/array/bsearch_spec.rb b/spec/ruby/core/array/bsearch_spec.rb
index 8fa6245dbf..12aec60654 100644
--- a/spec/ruby/core/array/bsearch_spec.rb
+++ b/spec/ruby/core/array/bsearch_spec.rb
@@ -3,26 +3,26 @@ require_relative '../enumerable/shared/enumeratorized'
 
 describe "Array#bsearch" do
   it "returns an Enumerator when not passed a block" do
-    [1].bsearch.should be_an_instance_of(Enumerator)
+    [1].bsearch.should.instance_of?(Enumerator)
   end
 
   it_behaves_like :enumeratorized_with_unknown_size, :bsearch, [1,2,3]
 
   it "raises a TypeError if the block returns an Object" do
-    -> { [1].bsearch { Object.new } }.should raise_error(TypeError)
+    -> { [1].bsearch { Object.new } }.should.raise(TypeError)
   end
 
   it "raises a TypeError if the block returns a String" do
-    -> { [1].bsearch { "1" } }.should raise_error(TypeError)
+    -> { [1].bsearch { "1" } }.should.raise(TypeError)
   end
 
   context "with a block returning true or false" do
     it "returns nil if the block returns false for every element" do
-      [0, 1, 2, 3].bsearch { |x| x > 3 }.should be_nil
+      [0, 1, 2, 3].bsearch { |x| x > 3 }.should == nil
     end
 
     it "returns nil if the block returns nil for every element" do
-      [0, 1, 2, 3].bsearch { |x| nil }.should be_nil
+      [0, 1, 2, 3].bsearch { |x| nil }.should == nil
     end
 
     it "returns element at zero if the block returns true for every element" do
@@ -38,21 +38,21 @@ describe "Array#bsearch" do
 
   context "with a block returning negative, zero, positive numbers" do
     it "returns nil if the block returns less than zero for every element" do
-      [0, 1, 2, 3].bsearch { |x| x <=> 5 }.should be_nil
+      [0, 1, 2, 3].bsearch { |x| x <=> 5 }.should == nil
     end
 
     it "returns nil if the block returns greater than zero for every element" do
-      [0, 1, 2, 3].bsearch { |x| x <=> -1 }.should be_nil
+      [0, 1, 2, 3].bsearch { |x| x <=> -1 }.should == nil
 
     end
 
     it "returns nil if the block never returns zero" do
-      [0, 1, 3, 4].bsearch { |x| x <=> 2 }.should be_nil
+      [0, 1, 3, 4].bsearch { |x| x <=> 2 }.should == nil
     end
 
     it "accepts (+/-)Float::INFINITY from the block" do
-      [0, 1, 3, 4].bsearch { |x| Float::INFINITY }.should be_nil
-      [0, 1, 3, 4].bsearch { |x| -Float::INFINITY }.should be_nil
+      [0, 1, 3, 4].bsearch { |x| Float::INFINITY }.should == nil
+      [0, 1, 3, 4].bsearch { |x| -Float::INFINITY }.should == nil
     end
 
     it "returns an element at an index for which block returns 0.0" do
@@ -62,17 +62,17 @@ describe "Array#bsearch" do
 
     it "returns an element at an index for which block returns 0" do
       result = [0, 1, 2, 3, 4].bsearch { |x| x < 1 ? 1 : x > 3 ? -1 : 0 }
-      [1, 2].should include(result)
+      [1, 2].should.include?(result)
     end
   end
 
   context "with a block that calls break" do
     it "returns nil if break is called without a value" do
-      ['a', 'b', 'c'].bsearch { |v| break }.should be_nil
+      ['a', 'b', 'c'].bsearch { |v| break }.should == nil
     end
 
     it "returns nil if break is called with a nil value" do
-      ['a', 'b', 'c'].bsearch { |v| break nil }.should be_nil
+      ['a', 'b', 'c'].bsearch { |v| break nil }.should == nil
     end
 
     it "returns object if break is called with an object" do
diff --git a/spec/ruby/core/array/clear_spec.rb b/spec/ruby/core/array/clear_spec.rb
index d399d5a373..15778f864f 100644
--- a/spec/ruby/core/array/clear_spec.rb
+++ b/spec/ruby/core/array/clear_spec.rb
@@ -4,49 +4,29 @@ require_relative 'fixtures/classes'
 describe "Array#clear" do
   it "removes all elements" do
     a = [1, 2, 3, 4]
-    a.clear.should equal(a)
+    a.clear.should.equal?(a)
     a.should == []
   end
 
   it "returns self" do
     a = [1]
-    a.should equal a.clear
+    a.should.equal? a.clear
   end
 
   it "leaves the Array empty" do
     a = [1]
     a.clear
-    a.empty?.should == true
+    a.should.empty?
     a.size.should == 0
   end
 
-  ruby_version_is ''...'2.7' do
-    it "keeps tainted status" do
-      a = [1]
-      a.taint
-      a.tainted?.should be_true
-      a.clear
-      a.tainted?.should be_true
-    end
-  end
-
   it "does not accept any arguments" do
-    -> { [1].clear(true) }.should raise_error(ArgumentError)
-  end
-
-  ruby_version_is ''...'2.7' do
-    it "keeps untrusted status" do
-      a = [1]
-      a.untrust
-      a.untrusted?.should be_true
-      a.clear
-      a.untrusted?.should be_true
-    end
+    -> { [1].clear(true) }.should.raise(ArgumentError)
   end
 
-  it "raises a #{frozen_error_class} on a frozen array" do
+  it "raises a FrozenError on a frozen array" do
     a = [1]
     a.freeze
-    -> { a.clear }.should raise_error(frozen_error_class)
+    -> { a.clear }.should.raise(FrozenError)
   end
 end
diff --git a/spec/ruby/core/array/clone_spec.rb b/spec/ruby/core/array/clone_spec.rb
index 803e746e02..7ce9d40a81 100644
--- a/spec/ruby/core/array/clone_spec.rb
+++ b/spec/ruby/core/array/clone_spec.rb
@@ -12,8 +12,8 @@ describe "Array#clone" do
     aa = a.clone
     bb = b.clone
 
-    aa.frozen?.should == true
-    bb.frozen?.should == false
+    aa.should.frozen?
+    bb.should_not.frozen?
   end
 
   it "copies singleton methods" do
@@ -23,9 +23,9 @@ describe "Array#clone" do
     aa = a.clone
     bb = b.clone
 
-    a.respond_to?(:a_singleton_method).should be_true
-    b.respond_to?(:a_singleton_method).should be_false
-    aa.respond_to?(:a_singleton_method).should be_true
-    bb.respond_to?(:a_singleton_method).should be_false
+    a.respond_to?(:a_singleton_method).should == true
+    b.respond_to?(:a_singleton_method).should == false
+    aa.respond_to?(:a_singleton_method).should == true
+    bb.respond_to?(:a_singleton_method).should == false
   end
 end
diff --git a/spec/ruby/core/array/collect_spec.rb b/spec/ruby/core/array/collect_spec.rb
index 0ad4c283b1..bdee5c240a 100644
--- a/spec/ruby/core/array/collect_spec.rb
+++ b/spec/ruby/core/array/collect_spec.rb
@@ -1,11 +1,13 @@
 require_relative '../../spec_helper'
-require_relative 'fixtures/classes'
-require_relative 'shared/collect'
 
 describe "Array#collect" do
-  it_behaves_like :array_collect, :collect
+  it "is an alias of Array#map" do
+    Array.instance_method(:collect).should == Array.instance_method(:map)
+  end
 end
 
 describe "Array#collect!" do
-  it_behaves_like :array_collect_b, :collect!
+  it "is an alias of Array#map!" do
+    Array.instance_method(:collect!).should == Array.instance_method(:map!)
+  end
 end
diff --git a/spec/ruby/core/array/combination_spec.rb b/spec/ruby/core/array/combination_spec.rb
index f16d6f98fc..ac570687ca 100644
--- a/spec/ruby/core/array/combination_spec.rb
+++ b/spec/ruby/core/array/combination_spec.rb
@@ -6,11 +6,11 @@ describe "Array#combination" do
   end
 
   it "returns an enumerator when no block is provided" do
-    @array.combination(2).should be_an_instance_of(Enumerator)
+    @array.combination(2).should.instance_of?(Enumerator)
   end
 
   it "returns self when a block is given" do
-    @array.combination(2){}.should equal(@array)
+    @array.combination(2){}.should.equal?(@array)
   end
 
   it "yields nothing for out of bounds length and return self" do
@@ -30,7 +30,7 @@ describe "Array#combination" do
   it "yields a copy of self if the argument is the size of the receiver" do
     r = @array.combination(4).to_a
     r.should == [@array]
-    r[0].should_not equal(@array)
+    r[0].should_not.equal?(@array)
   end
 
   it "yields [] when length is 0" do
diff --git a/spec/ruby/core/array/compact_spec.rb b/spec/ruby/core/array/compact_spec.rb
index ee3dfc0ca2..dbcd16da35 100644
--- a/spec/ruby/core/array/compact_spec.rb
+++ b/spec/ruby/core/array/compact_spec.rb
@@ -15,67 +15,37 @@ describe "Array#compact" do
 
   it "does not return self" do
     a = [1, 2, 3]
-    a.compact.should_not equal(a)
+    a.compact.should_not.equal?(a)
   end
 
   it "does not return subclass instance for Array subclasses" do
-    ArraySpecs::MyArray[1, 2, 3, nil].compact.should be_an_instance_of(Array)
-  end
-
-  ruby_version_is ''...'2.7' do
-    it "does not keep tainted status even if all elements are removed" do
-      a = [nil, nil]
-      a.taint
-      a.compact.tainted?.should be_false
-    end
-
-    it "does not keep untrusted status even if all elements are removed" do
-      a = [nil, nil]
-      a.untrust
-      a.compact.untrusted?.should be_false
-    end
+    ArraySpecs::MyArray[1, 2, 3, nil].compact.should.instance_of?(Array)
   end
 end
 
 describe "Array#compact!" do
   it "removes all nil elements" do
     a = ['a', nil, 'b', false, 'c']
-    a.compact!.should equal(a)
+    a.compact!.should.equal?(a)
     a.should == ["a", "b", false, "c"]
     a = [nil, 'a', 'b', false, 'c']
-    a.compact!.should equal(a)
+    a.compact!.should.equal?(a)
     a.should == ["a", "b", false, "c"]
     a = ['a', 'b', false, 'c', nil]
-    a.compact!.should equal(a)
+    a.compact!.should.equal?(a)
     a.should == ["a", "b", false, "c"]
   end
 
   it "returns self if some nil elements are removed" do
     a = ['a', nil, 'b', false, 'c']
-    a.compact!.should equal a
+    a.compact!.should.equal? a
   end
 
   it "returns nil if there are no nil elements to remove" do
     [1, 2, false, 3].compact!.should == nil
   end
 
-  ruby_version_is ''...'2.7' do
-    it "keeps tainted status even if all elements are removed" do
-      a = [nil, nil]
-      a.taint
-      a.compact!
-      a.tainted?.should be_true
-    end
-
-    it "keeps untrusted status even if all elements are removed" do
-      a = [nil, nil]
-      a.untrust
-      a.compact!
-      a.untrusted?.should be_true
-    end
-  end
-
-  it "raises a #{frozen_error_class} on a frozen array" do
-    -> { ArraySpecs.frozen_array.compact! }.should raise_error(frozen_error_class)
+  it "raises a FrozenError on a frozen array" do
+    -> { ArraySpecs.frozen_array.compact! }.should.raise(FrozenError)
   end
 end
diff --git a/spec/ruby/core/array/comparison_spec.rb b/spec/ruby/core/array/comparison_spec.rb
index 5d1c3265f1..14e8931e5a 100644
--- a/spec/ruby/core/array/comparison_spec.rb
+++ b/spec/ruby/core/array/comparison_spec.rb
@@ -92,6 +92,6 @@ describe "Array#<=>" do
   end
 
   it "returns nil when the argument is not array-like" do
-    ([] <=> false).should be_nil
+    ([] <=> false).should == nil
   end
 end
diff --git a/spec/ruby/core/array/concat_spec.rb b/spec/ruby/core/array/concat_spec.rb
index b297c091a3..1e8d20c36c 100644
--- a/spec/ruby/core/array/concat_spec.rb
+++ b/spec/ruby/core/array/concat_spec.rb
@@ -4,12 +4,12 @@ require_relative 'fixtures/classes'
 describe "Array#concat" do
   it "returns the array itself" do
     ary = [1,2,3]
-    ary.concat([4,5,6]).equal?(ary).should be_true
+    ary.concat([4,5,6]).equal?(ary).should == true
   end
 
   it "appends the elements in the other array" do
     ary = [1, 2, 3]
-    ary.concat([9, 10, 11]).should equal(ary)
+    ary.concat([9, 10, 11]).should.equal?(ary)
     ary.should == [1, 2, 3, 9, 10, 11]
     ary.concat([])
     ary.should == [1, 2, 3, 9, 10, 11]
@@ -32,71 +32,13 @@ describe "Array#concat" do
     [].concat(obj).should == [5, 6, 7]
   end
 
-  it "raises a #{frozen_error_class} when Array is frozen and modification occurs" do
-    -> { ArraySpecs.frozen_array.concat [1] }.should raise_error(frozen_error_class)
+  it "raises a FrozenError when Array is frozen and modification occurs" do
+    -> { ArraySpecs.frozen_array.concat [1] }.should.raise(FrozenError)
   end
 
   # see [ruby-core:23666]
-  it "raises a #{frozen_error_class} when Array is frozen and no modification occurs" do
-    -> { ArraySpecs.frozen_array.concat([]) }.should raise_error(frozen_error_class)
-  end
-
-  ruby_version_is ''...'2.7' do
-    it "keeps tainted status" do
-      ary = [1, 2]
-      ary.taint
-      ary.concat([3])
-      ary.tainted?.should be_true
-      ary.concat([])
-      ary.tainted?.should be_true
-    end
-
-    it "is not infected by the other" do
-      ary = [1,2]
-      other = [3]; other.taint
-      ary.tainted?.should be_false
-      ary.concat(other)
-      ary.tainted?.should be_false
-    end
-
-    it "keeps the tainted status of elements" do
-      ary = [ Object.new, Object.new, Object.new ]
-      ary.each {|x| x.taint }
-
-      ary.concat([ Object.new ])
-      ary[0].tainted?.should be_true
-      ary[1].tainted?.should be_true
-      ary[2].tainted?.should be_true
-      ary[3].tainted?.should be_false
-    end
-
-    it "keeps untrusted status" do
-      ary = [1, 2]
-      ary.untrust
-      ary.concat([3])
-      ary.untrusted?.should be_true
-      ary.concat([])
-      ary.untrusted?.should be_true
-    end
-
-    it "is not infected untrustedness by the other" do
-      ary = [1,2]
-      other = [3]; other.untrust
-      ary.untrusted?.should be_false
-      ary.concat(other)
-      ary.untrusted?.should be_false
-    end
-
-    it "keeps the untrusted status of elements" do
-      ary = [ Object.new, Object.new, Object.new ]
-      ary.each {|x| x.untrust }
-
-      ary.concat([ Object.new ])
-      ary[0].untrusted?.should be_true
-      ary[1].untrusted?.should be_true
-      ary[2].untrusted?.should be_true
-      ary[3].untrusted?.should be_false
-    end
+  it "raises a FrozenError when Array is frozen and no modification occurs" do
+    -> { ArraySpecs.frozen_array.concat([]) }.should.raise(FrozenError)
   end
 
   it "appends elements to an Array with enough capacity that has been shifted" do
@@ -126,7 +68,7 @@ describe "Array#concat" do
 
   it "returns self when given no arguments" do
     ary = [1, 2]
-    ary.concat.should equal(ary)
+    ary.concat.should.equal?(ary)
     ary.should == [1, 2]
   end
 end
diff --git a/spec/ruby/core/array/constructor_spec.rb b/spec/ruby/core/array/constructor_spec.rb
index 6f36074c45..c4398c535d 100644
--- a/spec/ruby/core/array/constructor_spec.rb
+++ b/spec/ruby/core/array/constructor_spec.rb
@@ -7,7 +7,7 @@ describe "Array.[]" do
     Array.[](5, true, nil, 'a', "Ruby", obj).should == [5, true, nil, "a", "Ruby", obj]
 
     a = ArraySpecs::MyArray.[](5, true, nil, 'a', "Ruby", obj)
-    a.should be_an_instance_of(ArraySpecs::MyArray)
+    a.should.instance_of?(ArraySpecs::MyArray)
     a.inspect.should == [5, true, nil, "a", "Ruby", obj].inspect
   end
 end
@@ -18,7 +18,7 @@ describe "Array[]" do
     Array[5, true, nil, 'a', "Ruby", obj].should == Array.[](5, true, nil, "a", "Ruby", obj)
 
     a = ArraySpecs::MyArray[5, true, nil, 'a', "Ruby", obj]
-    a.should be_an_instance_of(ArraySpecs::MyArray)
+    a.should.instance_of?(ArraySpecs::MyArray)
     a.inspect.should == [5, true, nil, "a", "Ruby", obj].inspect
   end
 end
diff --git a/spec/ruby/core/array/count_spec.rb b/spec/ruby/core/array/count_spec.rb
index eaf275aeb7..e778233c16 100644
--- a/spec/ruby/core/array/count_spec.rb
+++ b/spec/ruby/core/array/count_spec.rb
@@ -1,4 +1,5 @@
 require_relative '../../spec_helper'
+require_relative 'shared/iterable_and_tolerating_size_increasing'
 
 describe "Array#count" do
   it "returns the number of elements" do
@@ -12,4 +13,14 @@ describe "Array#count" do
   it "returns the number of element for which the block evaluates to true" do
     [:a, :b, :c].count { |s| s != :b }.should == 2
   end
+
+  it "ignores the block if there is an argument" do
+    -> {
+      [:a, :b, :b, :c].count(:b) { |e| e.size > 10 }.should == 2
+    }.should complain(/given block not used/)
+  end
+
+  context "when a block argument given" do
+    it_behaves_like :array_iterable_and_tolerating_size_increasing, :count
+  end
 end
diff --git a/spec/ruby/core/array/cycle_spec.rb b/spec/ruby/core/array/cycle_spec.rb
index 7219b49883..29284257e9 100644
--- a/spec/ruby/core/array/cycle_spec.rb
+++ b/spec/ruby/core/array/cycle_spec.rb
@@ -10,17 +10,17 @@ describe "Array#cycle" do
   end
 
   it "does not yield and returns nil when the array is empty and passed value is an integer" do
-    [].cycle(6, &@prc).should be_nil
+    [].cycle(6, &@prc).should == nil
     ScratchPad.recorded.should == []
   end
 
   it "does not yield and returns nil when the array is empty and passed value is nil" do
-    [].cycle(nil, &@prc).should be_nil
+    [].cycle(nil, &@prc).should == nil
     ScratchPad.recorded.should == []
   end
 
   it "does not yield and returns nil when passed 0" do
-    @array.cycle(0, &@prc).should be_nil
+    @array.cycle(0, &@prc).should == nil
     ScratchPad.recorded.should == []
   end
 
@@ -48,13 +48,13 @@ describe "Array#cycle" do
   it "does not rescue StopIteration when not passed a count" do
     -> do
       @array.cycle { raise StopIteration }
-    end.should raise_error(StopIteration)
+    end.should.raise(StopIteration)
   end
 
   it "does not rescue StopIteration when passed a count" do
     -> do
       @array.cycle(3) { raise StopIteration }
-    end.should raise_error(StopIteration)
+    end.should.raise(StopIteration)
   end
 
   it "iterates the array Integer(count) times when passed a Float count" do
@@ -74,23 +74,23 @@ describe "Array#cycle" do
     count = mock("cycle count 2")
     count.should_receive(:to_int).and_return("2")
 
-    -> { @array.cycle(count, &@prc) }.should raise_error(TypeError)
+    -> { @array.cycle(count, &@prc) }.should.raise(TypeError)
   end
 
   it "raises a TypeError if passed a String" do
-    -> { @array.cycle("4") { } }.should raise_error(TypeError)
+    -> { @array.cycle("4") { } }.should.raise(TypeError)
   end
 
   it "raises a TypeError if passed an Object" do
-    -> { @array.cycle(mock("cycle count")) { } }.should raise_error(TypeError)
+    -> { @array.cycle(mock("cycle count")) { } }.should.raise(TypeError)
   end
 
   it "raises a TypeError if passed true" do
-    -> { @array.cycle(true) { } }.should raise_error(TypeError)
+    -> { @array.cycle(true) { } }.should.raise(TypeError)
   end
 
   it "raises a TypeError if passed false" do
-    -> { @array.cycle(false) { } }.should raise_error(TypeError)
+    -> { @array.cycle(false) { } }.should.raise(TypeError)
   end
 
   before :all do
diff --git a/spec/ruby/core/array/deconstruct_spec.rb b/spec/ruby/core/array/deconstruct_spec.rb
index 2b07152dfc..11bb8e72c4 100644
--- a/spec/ruby/core/array/deconstruct_spec.rb
+++ b/spec/ruby/core/array/deconstruct_spec.rb
@@ -1,11 +1,9 @@
 require_relative '../../spec_helper'
 
-ruby_version_is "2.7" do
-  describe "Array#deconstruct" do
-    it "returns self" do
-      array = [1]
+describe "Array#deconstruct" do
+  it "returns self" do
+    array = [1]
 
-      array.deconstruct.should equal array
-    end
+    array.deconstruct.should.equal? array
   end
 end
diff --git a/spec/ruby/core/array/delete_at_spec.rb b/spec/ruby/core/array/delete_at_spec.rb
index 0ed56c18bb..1e298b6730 100644
--- a/spec/ruby/core/array/delete_at_spec.rb
+++ b/spec/ruby/core/array/delete_at_spec.rb
@@ -35,29 +35,7 @@ describe "Array#delete_at" do
     a.delete_at(-2).should == 1
   end
 
-  it "raises a #{frozen_error_class} on a frozen array" do
-    -> { [1,2,3].freeze.delete_at(0) }.should raise_error(frozen_error_class)
-  end
-
-  ruby_version_is ''...'2.7' do
-    it "keeps tainted status" do
-      ary = [1, 2]
-      ary.taint
-      ary.tainted?.should be_true
-      ary.delete_at(0)
-      ary.tainted?.should be_true
-      ary.delete_at(0) # now empty
-      ary.tainted?.should be_true
-    end
-
-    it "keeps untrusted status" do
-      ary = [1, 2]
-      ary.untrust
-      ary.untrusted?.should be_true
-      ary.delete_at(0)
-      ary.untrusted?.should be_true
-      ary.delete_at(0) # now empty
-      ary.untrusted?.should be_true
-    end
+  it "raises a FrozenError on a frozen array" do
+    -> { [1,2,3].freeze.delete_at(0) }.should.raise(FrozenError)
   end
 end
diff --git a/spec/ruby/core/array/delete_if_spec.rb b/spec/ruby/core/array/delete_if_spec.rb
index 2312917c41..701a612395 100644
--- a/spec/ruby/core/array/delete_if_spec.rb
+++ b/spec/ruby/core/array/delete_if_spec.rb
@@ -2,6 +2,7 @@ require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
 require_relative 'shared/enumeratorize'
 require_relative 'shared/delete_if'
+require_relative 'shared/iterable_and_tolerating_size_increasing'
 require_relative '../enumerable/shared/enumeratorized'
 
 describe "Array#delete_if" do
@@ -16,7 +17,7 @@ describe "Array#delete_if" do
   end
 
   it "returns self" do
-    @a.delete_if{ true }.equal?(@a).should be_true
+    @a.delete_if{ true }.equal?(@a).should == true
   end
 
   it_behaves_like :enumeratorize, :delete_if
@@ -24,45 +25,58 @@ describe "Array#delete_if" do
   it "returns self when called on an Array emptied with #shift" do
     array = [1]
     array.shift
-    array.delete_if { |x| true }.should equal(array)
+    array.delete_if { |x| true }.should.equal?(array)
   end
 
   it "returns an Enumerator if no block given, and the enumerator can modify the original array" do
     enum = @a.delete_if
-    enum.should be_an_instance_of(Enumerator)
-    @a.should_not be_empty
+    enum.should.instance_of?(Enumerator)
+    @a.should_not.empty?
     enum.each { true }
-    @a.should be_empty
+    @a.should.empty?
   end
 
   it "returns an Enumerator if no block given, and the array is frozen" do
-    @a.freeze.delete_if.should be_an_instance_of(Enumerator)
+    @a.freeze.delete_if.should.instance_of?(Enumerator)
   end
 
-  it "raises a #{frozen_error_class} on a frozen array" do
-    -> { ArraySpecs.frozen_array.delete_if {} }.should raise_error(frozen_error_class)
+  it "raises a FrozenError on a frozen array" do
+    -> { ArraySpecs.frozen_array.delete_if {} }.should.raise(FrozenError)
   end
 
-  it "raises a #{frozen_error_class} on an empty frozen array" do
-    -> { ArraySpecs.empty_frozen_array.delete_if {} }.should raise_error(frozen_error_class)
+  it "raises a FrozenError on an empty frozen array" do
+    -> { ArraySpecs.empty_frozen_array.delete_if {} }.should.raise(FrozenError)
   end
 
-  ruby_version_is ''...'2.7' do
-    it "keeps tainted status" do
-      @a.taint
-      @a.tainted?.should be_true
-      @a.delete_if{ true }
-      @a.tainted?.should be_true
+  it "does not truncate the array is the block raises an exception" do
+    a = [1, 2, 3]
+    begin
+      a.delete_if { raise StandardError, 'Oops' }
+    rescue
     end
 
-    it "keeps untrusted status" do
-      @a.untrust
-      @a.untrusted?.should be_true
-      @a.delete_if{ true }
-      @a.untrusted?.should be_true
+    a.should == [1, 2, 3]
+  end
+
+  it "only removes elements for which the block returns true, keeping the element which raised an error." do
+    a = [1, 2, 3, 4]
+    begin
+      a.delete_if do |e|
+        case e
+        when 2 then true
+        when 3 then raise StandardError, 'Oops'
+        else false
+        end
+      end
+    rescue StandardError
     end
+
+    a.should == [1, 3, 4]
   end
 
   it_behaves_like :enumeratorized_with_origin_size, :delete_if, [1,2,3]
   it_behaves_like :delete_if, :delete_if
+
+  @value_to_return = -> _ { false }
+  it_behaves_like :array_iterable_and_tolerating_size_increasing, :delete_if
 end
diff --git a/spec/ruby/core/array/delete_spec.rb b/spec/ruby/core/array/delete_spec.rb
index 41e211e660..0d80b2839d 100644
--- a/spec/ruby/core/array/delete_spec.rb
+++ b/spec/ruby/core/array/delete_spec.rb
@@ -40,29 +40,7 @@ describe "Array#delete" do
     [1, 2, 3].freeze.delete(0).should == nil
   end
 
-  it "raises a #{frozen_error_class} on a frozen array" do
-    -> { [1, 2, 3].freeze.delete(1) }.should raise_error(frozen_error_class)
-  end
-
-  ruby_version_is ''...'2.7' do
-    it "keeps tainted status" do
-      a = [1, 2]
-      a.taint
-      a.tainted?.should be_true
-      a.delete(2)
-      a.tainted?.should be_true
-      a.delete(1) # now empty
-      a.tainted?.should be_true
-    end
-
-    it "keeps untrusted status" do
-      a = [1, 2]
-      a.untrust
-      a.untrusted?.should be_true
-      a.delete(2)
-      a.untrusted?.should be_true
-      a.delete(1) # now empty
-      a.untrusted?.should be_true
-    end
+  it "raises a FrozenError on a frozen array" do
+    -> { [1, 2, 3].freeze.delete(1) }.should.raise(FrozenError)
   end
 end
diff --git a/spec/ruby/core/array/difference_spec.rb b/spec/ruby/core/array/difference_spec.rb
index a357657967..63e32feca0 100644
--- a/spec/ruby/core/array/difference_spec.rb
+++ b/spec/ruby/core/array/difference_spec.rb
@@ -2,23 +2,21 @@ require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
 require_relative 'shared/difference'
 
-ruby_version_is "2.6" do
-  describe "Array#difference" do
-    it_behaves_like :array_binary_difference, :difference
+describe "Array#difference" do
+  it_behaves_like :array_binary_difference, :difference
 
-    it "returns a copy when called without any parameter" do
-      x = [1, 2, 3, 2]
-      x.difference.should == x
-      x.difference.should_not equal x
-    end
+  it "returns a copy when called without any parameter" do
+    x = [1, 2, 3, 2]
+    x.difference.should == x
+    x.difference.should_not.equal? x
+  end
 
-    it "does not return subclass instances for Array subclasses" do
-      ArraySpecs::MyArray[1, 2, 3].difference.should be_an_instance_of(Array)
-    end
+  it "does not return subclass instances for Array subclasses" do
+    ArraySpecs::MyArray[1, 2, 3].difference.should.instance_of?(Array)
+  end
 
-    it "accepts multiple arguments" do
-      x = [1, 2, 3, 1]
-      x.difference([], [0, 1], [3, 4], [3]).should == [2]
-    end
+  it "accepts multiple arguments" do
+    x = [1, 2, 3, 1]
+    x.difference([], [0, 1], [3, 4], [3]).should == [2]
   end
 end
diff --git a/spec/ruby/core/array/dig_spec.rb b/spec/ruby/core/array/dig_spec.rb
index f2d8ff47fd..4166ff9f1f 100644
--- a/spec/ruby/core/array/dig_spec.rb
+++ b/spec/ruby/core/array/dig_spec.rb
@@ -4,7 +4,7 @@ describe "Array#dig" do
 
   it "returns #at with one arg" do
     ['a'].dig(0).should == 'a'
-    ['a'].dig(1).should be_nil
+    ['a'].dig(1).should == nil
   end
 
   it "recurses array elements" do
@@ -22,20 +22,20 @@ describe "Array#dig" do
   it "raises a TypeError for a non-numeric index" do
     -> {
       ['a'].dig(:first)
-    }.should raise_error(TypeError)
+    }.should.raise(TypeError)
   end
 
   it "raises a TypeError if any intermediate step does not respond to #dig" do
     a = [1, 2]
     -> {
       a.dig(0, 1)
-    }.should raise_error(TypeError)
+    }.should.raise(TypeError)
   end
 
   it "raises an ArgumentError if no arguments provided" do
     -> {
       [10].dig()
-    }.should raise_error(ArgumentError)
+    }.should.raise(ArgumentError)
   end
 
   it "returns nil if any intermediate step is nil" do
diff --git a/spec/ruby/core/array/drop_spec.rb b/spec/ruby/core/array/drop_spec.rb
index 84ea86b04c..c0e1c9edce 100644
--- a/spec/ruby/core/array/drop_spec.rb
+++ b/spec/ruby/core/array/drop_spec.rb
@@ -1,4 +1,5 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "Array#drop" do
   it "removes the specified number of elements from the start of the array" do
@@ -6,7 +7,7 @@ describe "Array#drop" do
   end
 
   it "raises an ArgumentError if the number of elements specified is negative" do
-   -> { [1, 2].drop(-3) }.should raise_error(ArgumentError)
+    -> { [1, 2].drop(-3) }.should.raise(ArgumentError)
   end
 
   it "returns an empty Array if all elements are dropped" do
@@ -39,13 +40,17 @@ describe "Array#drop" do
   end
 
   it "raises a TypeError when the passed argument can't be coerced to Integer" do
-    -> { [1, 2].drop("cat") }.should raise_error(TypeError)
+    -> { [1, 2].drop("cat") }.should.raise(TypeError)
   end
 
   it "raises a TypeError when the passed argument isn't an integer and #to_int returns non-Integer" do
     obj = mock("to_int")
     obj.should_receive(:to_int).and_return("cat")
 
-    -> { [1, 2].drop(obj) }.should raise_error(TypeError)
+    -> { [1, 2].drop(obj) }.should.raise(TypeError)
+  end
+
+  it 'returns a Array instance for Array subclasses' do
+    ArraySpecs::MyArray[1, 2, 3, 4, 5].drop(1).should.instance_of?(Array)
   end
 end
diff --git a/spec/ruby/core/array/drop_while_spec.rb b/spec/ruby/core/array/drop_while_spec.rb
index cfb6b1e267..4fead3ff06 100644
--- a/spec/ruby/core/array/drop_while_spec.rb
+++ b/spec/ruby/core/array/drop_while_spec.rb
@@ -1,6 +1,11 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+require_relative 'shared/iterable_and_tolerating_size_increasing'
 
 describe "Array#drop_while" do
+  @value_to_return = -> _ { true }
+  it_behaves_like :array_iterable_and_tolerating_size_increasing, :drop_while
+
   it "removes elements from the start of the array while the block evaluates to true" do
     [1, 2, 3, 4].drop_while { |n| n < 4 }.should == [4]
   end
@@ -12,4 +17,8 @@ describe "Array#drop_while" do
   it "removes elements from the start of the array until the block returns false" do
     [1, 2, 3, false, 5].drop_while { |n| n }.should == [false, 5]
   end
+
+  it 'returns a Array instance for Array subclasses' do
+    ArraySpecs::MyArray[1, 2, 3, 4, 5].drop_while { |n| n < 4 }.should.instance_of?(Array)
+  end
 end
diff --git a/spec/ruby/core/array/dup_spec.rb b/spec/ruby/core/array/dup_spec.rb
index 17f467d5fc..f14aeca3b5 100644
--- a/spec/ruby/core/array/dup_spec.rb
+++ b/spec/ruby/core/array/dup_spec.rb
@@ -12,8 +12,8 @@ describe "Array#dup" do
     aa = a.dup
     bb = b.dup
 
-    aa.frozen?.should be_false
-    bb.frozen?.should be_false
+    aa.frozen?.should == false
+    bb.frozen?.should == false
   end
 
   it "does not copy singleton methods" do
@@ -23,9 +23,9 @@ describe "Array#dup" do
     aa = a.dup
     bb = b.dup
 
-    a.respond_to?(:a_singleton_method).should be_true
-    b.respond_to?(:a_singleton_method).should be_false
-    aa.respond_to?(:a_singleton_method).should be_false
-    bb.respond_to?(:a_singleton_method).should be_false
+    a.respond_to?(:a_singleton_method).should == true
+    b.respond_to?(:a_singleton_method).should == false
+    aa.respond_to?(:a_singleton_method).should == false
+    bb.respond_to?(:a_singleton_method).should == false
   end
 end
diff --git a/spec/ruby/core/array/each_index_spec.rb b/spec/ruby/core/array/each_index_spec.rb
index 51af5842c4..b238a89d8a 100644
--- a/spec/ruby/core/array/each_index_spec.rb
+++ b/spec/ruby/core/array/each_index_spec.rb
@@ -5,7 +5,7 @@ require_relative '../enumerable/shared/enumeratorized'
 
 # Modifying a collection while the contents are being iterated
 # gives undefined behavior. See
-# http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/23633
+# https://blade.ruby-lang.org/ruby-core/23633
 
 describe "Array#each_index" do
   before :each do
@@ -20,7 +20,7 @@ describe "Array#each_index" do
 
   it "returns self" do
     a = [:a, :b, :c]
-    a.each_index { |i| }.should equal(a)
+    a.each_index { |i| }.should.equal?(a)
   end
 
   it "is not confused by removing elements from the front" do
@@ -40,3 +40,19 @@ describe "Array#each_index" do
   it_behaves_like :enumeratorize, :each_index
   it_behaves_like :enumeratorized_with_origin_size, :each_index, [1,2,3]
 end
+
+describe "Array#each_index" do
+  it "tolerates increasing an array size during iteration" do
+    array = [:a, :b, :c]
+    ScratchPad.record []
+    i = 0
+
+    array.each_index do |index|
+      ScratchPad << index
+      array << i if i < 100
+      i += 1
+    end
+
+    ScratchPad.recorded.should == (0..102).to_a # element indices
+  end
+end
diff --git a/spec/ruby/core/array/each_spec.rb b/spec/ruby/core/array/each_spec.rb
index 256647d61e..73a4c36b17 100644
--- a/spec/ruby/core/array/each_spec.rb
+++ b/spec/ruby/core/array/each_spec.rb
@@ -1,20 +1,50 @@
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
 require_relative 'shared/enumeratorize'
+require_relative 'shared/iterable_and_tolerating_size_increasing'
 require_relative '../enumerable/shared/enumeratorized'
 
-# Modifying a collection while the contents are being iterated
-# gives undefined behavior. See
-# http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/23633
+# Mutating the array while it is being iterated is discouraged as it can result in confusing behavior.
+# Yet a Ruby implementation must not crash in such a case, and following the simple CRuby behavior makes sense.
+# CRuby simply reads the array storage and checks the size for every iteration;
+# like `i = 0; while i < size; yield self[i]; i += 1; end`
 
 describe "Array#each" do
   it "yields each element to the block" do
     a = []
     x = [1, 2, 3]
-    x.each { |item| a << item }.should equal(x)
+    x.each { |item| a << item }.should.equal?(x)
     a.should == [1, 2, 3]
   end
 
+  it "yields each element to the block even if the array is changed during iteration" do
+    a = [1, 2, 3, 4, 5]
+    iterated = []
+    a.each { |x| iterated << x; a << x+5 if x.even? }
+    iterated.should == [1, 2, 3, 4, 5, 7, 9]
+  end
+
+  it "yields only elements that are still in the array" do
+    a = [0, 1, 2, 3, 4]
+    iterated = []
+    a.each { |x| iterated << x; a.pop if x.even? }
+    iterated.should == [0, 1, 2]
+  end
+
+  it "yields elements based on an internal index" do
+    a = [0, 1, 2, 3, 4]
+    iterated = []
+    a.each { |x| iterated << x; a.shift if x.even? }
+    iterated.should == [0, 2, 4]
+  end
+
+  it "yields the same element multiple times if inserting while iterating" do
+    a = [1, 2]
+    iterated = []
+    a.each { |x| iterated << x; a.unshift(0) if a.size == 2 }
+    iterated.should == [1, 1, 2]
+  end
+
   it "yields each element to a block that takes multiple arguments" do
     a = [[1, 2], :a, [3, 4]]
     b = []
@@ -46,3 +76,7 @@ describe "Array#each" do
   it_behaves_like :enumeratorize, :each
   it_behaves_like :enumeratorized_with_origin_size, :each, [1,2,3]
 end
+
+describe "Array#each" do
+  it_behaves_like :array_iterable_and_tolerating_size_increasing, :each
+end
diff --git a/spec/ruby/core/array/element_reference_spec.rb b/spec/ruby/core/array/element_reference_spec.rb
index 31e5578a09..d5f4b54961 100644
--- a/spec/ruby/core/array/element_reference_spec.rb
+++ b/spec/ruby/core/array/element_reference_spec.rb
@@ -1,9 +1,862 @@
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
-require_relative 'shared/slice'
 
 describe "Array#[]" do
-  it_behaves_like :array_slice, :[]
+  it "returns the element at index with [index]" do
+    [ "a", "b", "c", "d", "e" ][1].should == "b"
+
+    a = [1, 2, 3, 4]
+
+    a[0].should == 1
+    a[1].should == 2
+    a[2].should == 3
+    a[3].should == 4
+    a[4].should == nil
+    a[10].should == nil
+
+    a.should == [1, 2, 3, 4]
+  end
+
+  it "returns the element at index from the end of the array with [-index]" do
+    [ "a", "b", "c", "d", "e" ][-2].should == "d"
+
+    a = [1, 2, 3, 4]
+
+    a[-1].should == 4
+    a[-2].should == 3
+    a[-3].should == 2
+    a[-4].should == 1
+    a[-5].should == nil
+    a[-10].should == nil
+
+    a.should == [1, 2, 3, 4]
+  end
+
+  it "returns count elements starting from index with [index, count]" do
+    [ "a", "b", "c", "d", "e" ][2, 3].should == ["c", "d", "e"]
+
+    a = [1, 2, 3, 4]
+
+    a[0, 0].should == []
+    a[0, 1].should == [1]
+    a[0, 2].should == [1, 2]
+    a[0, 4].should == [1, 2, 3, 4]
+    a[0, 6].should == [1, 2, 3, 4]
+    a[0, -1].should == nil
+    a[0, -2].should == nil
+    a[0, -4].should == nil
+
+    a[2, 0].should == []
+    a[2, 1].should == [3]
+    a[2, 2].should == [3, 4]
+    a[2, 4].should == [3, 4]
+    a[2, -1].should == nil
+
+    a[4, 0].should == []
+    a[4, 2].should == []
+    a[4, -1].should == nil
+
+    a[5, 0].should == nil
+    a[5, 2].should == nil
+    a[5, -1].should == nil
+
+    a[6, 0].should == nil
+    a[6, 2].should == nil
+    a[6, -1].should == nil
+
+    a.should == [1, 2, 3, 4]
+  end
+
+  it "returns count elements starting at index from the end of array with [-index, count]" do
+    [ "a", "b", "c", "d", "e" ][-2, 2].should == ["d", "e"]
+
+    a = [1, 2, 3, 4]
+
+    a[-1, 0].should == []
+    a[-1, 1].should == [4]
+    a[-1, 2].should == [4]
+    a[-1, -1].should == nil
+
+    a[-2, 0].should == []
+    a[-2, 1].should == [3]
+    a[-2, 2].should == [3, 4]
+    a[-2, 4].should == [3, 4]
+    a[-2, -1].should == nil
+
+    a[-4, 0].should == []
+    a[-4, 1].should == [1]
+    a[-4, 2].should == [1, 2]
+    a[-4, 4].should == [1, 2, 3, 4]
+    a[-4, 6].should == [1, 2, 3, 4]
+    a[-4, -1].should == nil
+
+    a[-5, 0].should == nil
+    a[-5, 1].should == nil
+    a[-5, 10].should == nil
+    a[-5, -1].should == nil
+
+    a.should == [1, 2, 3, 4]
+  end
+
+  it "returns the first count elements with [0, count]" do
+    [ "a", "b", "c", "d", "e" ][0, 3].should == ["a", "b", "c"]
+  end
+
+  it "returns the subarray which is independent to self with [index,count]" do
+    a = [1, 2, 3]
+    sub = a[1, 2]
+    sub.replace([:a, :b])
+    a.should == [1, 2, 3]
+  end
+
+  it "tries to convert the passed argument to an Integer using #to_int" do
+    obj = mock('to_int')
+    obj.stub!(:to_int).and_return(2)
+
+    a = [1, 2, 3, 4]
+    a[obj].should == 3
+    a[obj, 1].should == [3]
+    a[obj, obj].should == [3, 4]
+    a[0, obj].should == [1, 2]
+  end
+
+  it "raises TypeError if to_int returns non-integer" do
+    from = mock('from')
+    to = mock('to')
+
+    # So we can construct a range out of them...
+    def from.<=>(o) 0 end
+    def to.<=>(o) 0 end
+
+    a = [1, 2, 3, 4, 5]
+
+    def from.to_int() 'cat' end
+    def to.to_int() -2 end
+
+    -> { a[from..to] }.should.raise(TypeError)
+
+    def from.to_int() 1 end
+    def to.to_int() 'cat' end
+
+    -> { a[from..to] }.should.raise(TypeError)
+  end
+
+  it "returns the elements specified by Range indexes with [m..n]" do
+    [ "a", "b", "c", "d", "e" ][1..3].should == ["b", "c", "d"]
+    [ "a", "b", "c", "d", "e" ][4..-1].should == ['e']
+    [ "a", "b", "c", "d", "e" ][3..3].should == ['d']
+    [ "a", "b", "c", "d", "e" ][3..-2].should == ['d']
+    ['a'][0..-1].should == ['a']
+
+    a = [1, 2, 3, 4]
+
+    a[0..-10].should == []
+    a[0..0].should == [1]
+    a[0..1].should == [1, 2]
+    a[0..2].should == [1, 2, 3]
+    a[0..3].should == [1, 2, 3, 4]
+    a[0..4].should == [1, 2, 3, 4]
+    a[0..10].should == [1, 2, 3, 4]
+
+    a[2..-10].should == []
+    a[2..0].should == []
+    a[2..2].should == [3]
+    a[2..3].should == [3, 4]
+    a[2..4].should == [3, 4]
+
+    a[3..0].should == []
+    a[3..3].should == [4]
+    a[3..4].should == [4]
+
+    a[4..0].should == []
+    a[4..4].should == []
+    a[4..5].should == []
+
+    a[5..0].should == nil
+    a[5..5].should == nil
+    a[5..6].should == nil
+
+    a.should == [1, 2, 3, 4]
+  end
+
+  it "returns elements specified by Range indexes except the element at index n with [m...n]" do
+    [ "a", "b", "c", "d", "e" ][1...3].should == ["b", "c"]
+
+    a = [1, 2, 3, 4]
+
+    a[0...-10].should == []
+    a[0...0].should == []
+    a[0...1].should == [1]
+    a[0...2].should == [1, 2]
+    a[0...3].should == [1, 2, 3]
+    a[0...4].should == [1, 2, 3, 4]
+    a[0...10].should == [1, 2, 3, 4]
+
+    a[2...-10].should == []
+    a[2...0].should == []
+    a[2...2].should == []
+    a[2...3].should == [3]
+    a[2...4].should == [3, 4]
+
+    a[3...0].should == []
+    a[3...3].should == []
+    a[3...4].should == [4]
+
+    a[4...0].should == []
+    a[4...4].should == []
+    a[4...5].should == []
+
+    a[5...0].should == nil
+    a[5...5].should == nil
+    a[5...6].should == nil
+
+    a.should == [1, 2, 3, 4]
+  end
+
+  it "returns elements that exist if range start is in the array but range end is not with [m..n]" do
+    [ "a", "b", "c", "d", "e" ][4..7].should == ["e"]
+  end
+
+  it "accepts Range instances having a negative m and both signs for n with [m..n] and [m...n]" do
+    a = [1, 2, 3, 4]
+
+    a[-1..-1].should == [4]
+    a[-1...-1].should == []
+    a[-1..3].should == [4]
+    a[-1...3].should == []
+    a[-1..4].should == [4]
+    a[-1...4].should == [4]
+    a[-1..10].should == [4]
+    a[-1...10].should == [4]
+    a[-1..0].should == []
+    a[-1..-4].should == []
+    a[-1...-4].should == []
+    a[-1..-6].should == []
+    a[-1...-6].should == []
+
+    a[-2..-2].should == [3]
+    a[-2...-2].should == []
+    a[-2..-1].should == [3, 4]
+    a[-2...-1].should == [3]
+    a[-2..10].should == [3, 4]
+    a[-2...10].should == [3, 4]
+
+    a[-4..-4].should == [1]
+    a[-4..-2].should == [1, 2, 3]
+    a[-4...-2].should == [1, 2]
+    a[-4..-1].should == [1, 2, 3, 4]
+    a[-4...-1].should == [1, 2, 3]
+    a[-4..3].should == [1, 2, 3, 4]
+    a[-4...3].should == [1, 2, 3]
+    a[-4..4].should == [1, 2, 3, 4]
+    a[-4...4].should == [1, 2, 3, 4]
+    a[-4...4].should == [1, 2, 3, 4]
+    a[-4..0].should == [1]
+    a[-4...0].should == []
+    a[-4..1].should == [1, 2]
+    a[-4...1].should == [1]
+
+    a[-5..-5].should == nil
+    a[-5...-5].should == nil
+    a[-5..-4].should == nil
+    a[-5..-1].should == nil
+    a[-5..10].should == nil
+
+    a.should == [1, 2, 3, 4]
+  end
+
+  it "returns the subarray which is independent to self with [m..n]" do
+    a = [1, 2, 3]
+    sub = a[1..2]
+    sub.replace([:a, :b])
+    a.should == [1, 2, 3]
+  end
+
+  it "tries to convert Range elements to Integers using #to_int with [m..n] and [m...n]" do
+    from = mock('from')
+    to = mock('to')
+
+    # So we can construct a range out of them...
+    def from.<=>(o) 0 end
+    def to.<=>(o) 0 end
+
+    def from.to_int() 1 end
+    def to.to_int() -2 end
+
+    a = [1, 2, 3, 4]
+
+    a[from..to].should == [2, 3]
+    a[from...to].should == [2]
+    a[1..0].should == []
+    a[1...0].should == []
+
+    -> { a["a" .. "b"] }.should.raise(TypeError)
+    -> { a["a" ... "b"] }.should.raise(TypeError)
+    -> { a[from .. "b"] }.should.raise(TypeError)
+    -> { a[from ... "b"] }.should.raise(TypeError)
+  end
+
+  it "returns the same elements as [m..n] and [m...n] with Range subclasses" do
+    a = [1, 2, 3, 4]
+    range_incl = ArraySpecs::MyRange.new(1, 2)
+    range_excl = ArraySpecs::MyRange.new(-3, -1, true)
+
+    a[range_incl].should == [2, 3]
+    a[range_excl].should == [2, 3]
+  end
+
+  it "returns nil for a requested index not in the array with [index]" do
+    [ "a", "b", "c", "d", "e" ][5].should == nil
+  end
+
+  it "returns [] if the index is valid but length is zero with [index, length]" do
+    [ "a", "b", "c", "d", "e" ][0, 0].should == []
+    [ "a", "b", "c", "d", "e" ][2, 0].should == []
+  end
+
+  it "returns nil if length is zero but index is invalid with [index, length]" do
+    [ "a", "b", "c", "d", "e" ][100, 0].should == nil
+    [ "a", "b", "c", "d", "e" ][-50, 0].should == nil
+  end
+
+  # This is by design. It is in the official documentation.
+  it "returns [] if index == array.size with [index, length]" do
+    %w|a b c d e|[5, 2].should == []
+  end
+
+  it "returns nil if index > array.size with [index, length]" do
+    %w|a b c d e|[6, 2].should == nil
+  end
+
+  it "returns nil if length is negative with [index, length]" do
+    %w|a b c d e|[3, -1].should == nil
+    %w|a b c d e|[2, -2].should == nil
+    %w|a b c d e|[1, -100].should == nil
+  end
+
+  it "returns nil if no requested index is in the array with [m..n]" do
+    [ "a", "b", "c", "d", "e" ][6..10].should == nil
+  end
+
+  it "returns nil if range start is not in the array with [m..n]" do
+    [ "a", "b", "c", "d", "e" ][-10..2].should == nil
+    [ "a", "b", "c", "d", "e" ][10..12].should == nil
+  end
+
+  it "returns an empty array when m == n with [m...n]" do
+    [1, 2, 3, 4, 5][1...1].should == []
+  end
+
+  it "returns an empty array with [0...0]" do
+    [1, 2, 3, 4, 5][0...0].should == []
+  end
+
+  it "returns a subarray where m, n negatives and m < n with [m..n]" do
+    [ "a", "b", "c", "d", "e" ][-3..-2].should == ["c", "d"]
+  end
+
+  it "returns an array containing the first element with [0..0]" do
+    [1, 2, 3, 4, 5][0..0].should == [1]
+  end
+
+  it "returns the entire array with [0..-1]" do
+    [1, 2, 3, 4, 5][0..-1].should == [1, 2, 3, 4, 5]
+  end
+
+  it "returns all but the last element with [0...-1]" do
+    [1, 2, 3, 4, 5][0...-1].should == [1, 2, 3, 4]
+  end
+
+  it "returns [3] for [2..-1] out of [1, 2, 3]" do
+    [1,2,3][2..-1].should == [3]
+  end
+
+  it "returns an empty array when m > n and m, n are positive with [m..n]" do
+    [1, 2, 3, 4, 5][3..2].should == []
+  end
+
+  it "returns an empty array when m > n and m, n are negative with [m..n]" do
+    [1, 2, 3, 4, 5][-2..-3].should == []
+  end
+
+  it "does not expand array when the indices are outside of the array bounds" do
+    a = [1, 2]
+    a[4].should == nil
+    a.should == [1, 2]
+    a[4, 0].should == nil
+    a.should == [1, 2]
+    a[6, 1].should == nil
+    a.should == [1, 2]
+    a[8...8].should == nil
+    a.should == [1, 2]
+    a[10..10].should == nil
+    a.should == [1, 2]
+  end
+
+  describe "with a subclass of Array" do
+    before :each do
+      ScratchPad.clear
+
+      @array = ArraySpecs::MyArray[1, 2, 3, 4, 5]
+    end
+
+    it "returns a Array instance with [n, m]" do
+      @array[0, 2].should.instance_of?(Array)
+    end
+
+    it "returns a Array instance with [-n, m]" do
+      @array[-3, 2].should.instance_of?(Array)
+    end
+
+    it "returns a Array instance with [n..m]" do
+      @array[1..3].should.instance_of?(Array)
+    end
+
+    it "returns a Array instance with [n...m]" do
+      @array[1...3].should.instance_of?(Array)
+    end
+
+    it "returns a Array instance with [-n..-m]" do
+      @array[-3..-1].should.instance_of?(Array)
+    end
+
+    it "returns a Array instance with [-n...-m]" do
+      @array[-3...-1].should.instance_of?(Array)
+    end
+
+    it "returns an empty array when m == n with [m...n]" do
+      @array[1...1].should == []
+      ScratchPad.recorded.should == nil
+    end
+
+    it "returns an empty array with [0...0]" do
+      @array[0...0].should == []
+      ScratchPad.recorded.should == nil
+    end
+
+    it "returns an empty array when m > n and m, n are positive with [m..n]" do
+      @array[3..2].should == []
+      ScratchPad.recorded.should == nil
+    end
+
+    it "returns an empty array when m > n and m, n are negative with [m..n]" do
+      @array[-2..-3].should == []
+      ScratchPad.recorded.should == nil
+    end
+
+    it "returns [] if index == array.size with [index, length]" do
+      @array[5, 2].should == []
+      ScratchPad.recorded.should == nil
+    end
+
+    it "returns [] if the index is valid but length is zero with [index, length]" do
+      @array[0, 0].should == []
+      @array[2, 0].should == []
+      ScratchPad.recorded.should == nil
+    end
+
+    it "does not call #initialize on the subclass instance" do
+      @array[0, 3].should == [1, 2, 3]
+      ScratchPad.recorded.should == nil
+    end
+  end
+
+  it "raises a RangeError when the start index is out of range of Fixnum" do
+    array = [1, 2, 3, 4, 5, 6]
+    obj = mock('large value')
+    obj.should_receive(:to_int).and_return(bignum_value)
+    -> { array[obj] }.should.raise(RangeError)
+
+    obj = 8e19
+    -> { array[obj] }.should.raise(RangeError)
+
+    # boundary value when longs are 64 bits
+    -> { array[2.0**63] }.should.raise(RangeError)
+
+    # just under the boundary value when longs are 64 bits
+    array[max_long.to_f.prev_float].should == nil
+  end
+
+  it "raises a RangeError when the length is out of range of Fixnum" do
+    array = [1, 2, 3, 4, 5, 6]
+    obj = mock('large value')
+    obj.should_receive(:to_int).and_return(bignum_value)
+    -> { array[1, obj] }.should.raise(RangeError)
+
+    obj = 8e19
+    -> { array[1, obj] }.should.raise(RangeError)
+  end
+
+  it "raises a type error if a range is passed with a length" do
+    ->{ [1, 2, 3][1..2, 1] }.should.raise(TypeError)
+  end
+
+  it "raises a RangeError if passed a range with a bound that is too large" do
+    array = [1, 2, 3, 4, 5, 6]
+    -> { array[bignum_value..(bignum_value + 1)] }.should.raise(RangeError)
+    -> { array[0..bignum_value] }.should.raise(RangeError)
+  end
+
+  it "can accept endless ranges" do
+    a = [0, 1, 2, 3, 4, 5]
+    a[eval("(2..)")].should == [2, 3, 4, 5]
+    a[eval("(2...)")].should == [2, 3, 4, 5]
+    a[eval("(-2..)")].should == [4, 5]
+    a[eval("(-2...)")].should == [4, 5]
+    a[eval("(9..)")].should == nil
+    a[eval("(9...)")].should == nil
+    a[eval("(-9..)")].should == nil
+    a[eval("(-9...)")].should == nil
+  end
+
+  describe "can be sliced with Enumerator::ArithmeticSequence" do
+    before :each do
+      @array = [0, 1, 2, 3, 4, 5]
+    end
+
+    it "has endless range and positive steps" do
+      @array[eval("(0..).step(1)")].should == [0, 1, 2, 3, 4, 5]
+      @array[eval("(0..).step(2)")].should == [0, 2, 4]
+      @array[eval("(0..).step(10)")].should == [0]
+
+      @array[eval("(2..).step(1)")].should == [2, 3, 4, 5]
+      @array[eval("(2..).step(2)")].should == [2, 4]
+      @array[eval("(2..).step(10)")].should == [2]
+
+      @array[eval("(-3..).step(1)")].should == [3, 4, 5]
+      @array[eval("(-3..).step(2)")].should == [3, 5]
+      @array[eval("(-3..).step(10)")].should == [3]
+    end
+
+    it "has beginless range and positive steps" do
+      # end with zero index
+      @array[(..0).step(1)].should == [0]
+      @array[(...0).step(1)].should == []
+
+      @array[(..0).step(2)].should == [0]
+      @array[(...0).step(2)].should == []
+
+      @array[(..0).step(10)].should == [0]
+      @array[(...0).step(10)].should == []
+
+      # end with positive index
+      @array[(..3).step(1)].should == [0, 1, 2, 3]
+      @array[(...3).step(1)].should == [0, 1, 2]
+
+      @array[(..3).step(2)].should == [0, 2]
+      @array[(...3).step(2)].should == [0, 2]
+
+      @array[(..3).step(10)].should == [0]
+      @array[(...3).step(10)].should == [0]
+
+      # end with negative index
+      @array[(..-2).step(1)].should == [0, 1, 2, 3, 4,]
+      @array[(...-2).step(1)].should == [0, 1, 2, 3]
+
+      @array[(..-2).step(2)].should == [0, 2, 4]
+      @array[(...-2).step(2)].should == [0, 2]
+
+      @array[(..-2).step(10)].should == [0]
+      @array[(...-2).step(10)].should == [0]
+    end
+
+    it "has endless range and negative steps" do
+      @array[eval("(0..).step(-1)")].should == [0]
+      @array[eval("(0..).step(-2)")].should == [0]
+      @array[eval("(0..).step(-10)")].should == [0]
+
+      @array[eval("(2..).step(-1)")].should == [2, 1, 0]
+      @array[eval("(2..).step(-2)")].should == [2, 0]
+
+      @array[eval("(-3..).step(-1)")].should == [3, 2, 1, 0]
+      @array[eval("(-3..).step(-2)")].should == [3, 1]
+    end
+
+    it "has closed range and positive steps" do
+      # start and end with 0
+      @array[eval("(0..0).step(1)")].should == [0]
+      @array[eval("(0...0).step(1)")].should == []
+
+      @array[eval("(0..0).step(2)")].should == [0]
+      @array[eval("(0...0).step(2)")].should == []
+
+      @array[eval("(0..0).step(10)")].should == [0]
+      @array[eval("(0...0).step(10)")].should == []
+
+      # start and end with positive index
+      @array[eval("(1..3).step(1)")].should == [1, 2, 3]
+      @array[eval("(1...3).step(1)")].should == [1, 2]
+
+      @array[eval("(1..3).step(2)")].should == [1, 3]
+      @array[eval("(1...3).step(2)")].should == [1]
+
+      @array[eval("(1..3).step(10)")].should == [1]
+      @array[eval("(1...3).step(10)")].should == [1]
+
+      # start with positive index, end with negative index
+      @array[eval("(1..-2).step(1)")].should == [1, 2, 3, 4]
+      @array[eval("(1...-2).step(1)")].should == [1, 2, 3]
+
+      @array[eval("(1..-2).step(2)")].should ==  [1, 3]
+      @array[eval("(1...-2).step(2)")].should ==  [1, 3]
+
+      @array[eval("(1..-2).step(10)")].should == [1]
+      @array[eval("(1...-2).step(10)")].should == [1]
+
+      # start with negative index, end with positive index
+      @array[eval("(-4..4).step(1)")].should == [2, 3, 4]
+      @array[eval("(-4...4).step(1)")].should == [2, 3]
+
+      @array[eval("(-4..4).step(2)")].should == [2, 4]
+      @array[eval("(-4...4).step(2)")].should == [2]
+
+      @array[eval("(-4..4).step(10)")].should == [2]
+      @array[eval("(-4...4).step(10)")].should == [2]
+
+      # start with negative index, end with negative index
+      @array[eval("(-4..-2).step(1)")].should == [2, 3, 4]
+      @array[eval("(-4...-2).step(1)")].should == [2, 3]
+
+      @array[eval("(-4..-2).step(2)")].should == [2, 4]
+      @array[eval("(-4...-2).step(2)")].should == [2]
+
+      @array[eval("(-4..-2).step(10)")].should == [2]
+      @array[eval("(-4...-2).step(10)")].should == [2]
+    end
+
+    it "has closed range and negative steps" do
+      # start and end with 0
+      @array[eval("(0..0).step(-1)")].should == [0]
+      @array[eval("(0...0).step(-1)")].should == []
+
+      @array[eval("(0..0).step(-2)")].should == [0]
+      @array[eval("(0...0).step(-2)")].should == []
+
+      @array[eval("(0..0).step(-10)")].should == [0]
+      @array[eval("(0...0).step(-10)")].should == []
+
+      # start and end with positive index
+      @array[eval("(1..3).step(-1)")].should == []
+      @array[eval("(1...3).step(-1)")].should == []
+
+      @array[eval("(1..3).step(-2)")].should == []
+      @array[eval("(1...3).step(-2)")].should == []
+
+      @array[eval("(1..3).step(-10)")].should == []
+      @array[eval("(1...3).step(-10)")].should == []
+
+      # start with positive index, end with negative index
+      @array[eval("(1..-2).step(-1)")].should == []
+      @array[eval("(1...-2).step(-1)")].should == []
+
+      @array[eval("(1..-2).step(-2)")].should ==  []
+      @array[eval("(1...-2).step(-2)")].should ==  []
+
+      @array[eval("(1..-2).step(-10)")].should == []
+      @array[eval("(1...-2).step(-10)")].should == []
+
+      # start with negative index, end with positive index
+      @array[eval("(-4..4).step(-1)")].should == []
+      @array[eval("(-4...4).step(-1)")].should == []
+
+      @array[eval("(-4..4).step(-2)")].should == []
+      @array[eval("(-4...4).step(-2)")].should == []
+
+      @array[eval("(-4..4).step(-10)")].should == []
+      @array[eval("(-4...4).step(-10)")].should == []
+
+      # start with negative index, end with negative index
+      @array[eval("(-4..-2).step(-1)")].should == []
+      @array[eval("(-4...-2).step(-1)")].should == []
+
+      @array[eval("(-4..-2).step(-2)")].should == []
+      @array[eval("(-4...-2).step(-2)")].should == []
+
+      @array[eval("(-4..-2).step(-10)")].should == []
+      @array[eval("(-4...-2).step(-10)")].should == []
+    end
+
+    it "has inverted closed range and positive steps" do
+      # start and end with positive index
+      @array[eval("(3..1).step(1)")].should == []
+      @array[eval("(3...1).step(1)")].should == []
+
+      @array[eval("(3..1).step(2)")].should == []
+      @array[eval("(3...1).step(2)")].should == []
+
+      @array[eval("(3..1).step(10)")].should == []
+      @array[eval("(3...1).step(10)")].should == []
+
+      # start with negative index, end with positive index
+      @array[eval("(-2..1).step(1)")].should == []
+      @array[eval("(-2...1).step(1)")].should == []
+
+      @array[eval("(-2..1).step(2)")].should ==  []
+      @array[eval("(-2...1).step(2)")].should ==  []
+
+      @array[eval("(-2..1).step(10)")].should == []
+      @array[eval("(-2...1).step(10)")].should == []
+
+      # start with positive index, end with negative index
+      @array[eval("(4..-4).step(1)")].should == []
+      @array[eval("(4...-4).step(1)")].should == []
+
+      @array[eval("(4..-4).step(2)")].should == []
+      @array[eval("(4...-4).step(2)")].should == []
+
+      @array[eval("(4..-4).step(10)")].should == []
+      @array[eval("(4...-4).step(10)")].should == []
+
+      # start with negative index, end with negative index
+      @array[eval("(-2..-4).step(1)")].should == []
+      @array[eval("(-2...-4).step(1)")].should == []
+
+      @array[eval("(-2..-4).step(2)")].should == []
+      @array[eval("(-2...-4).step(2)")].should == []
+
+      @array[eval("(-2..-4).step(10)")].should == []
+      @array[eval("(-2...-4).step(10)")].should == []
+    end
+
+    it "has range with bounds outside of array" do
+      # end is equal to array's length
+      @array[(0..6).step(1)].should == [0, 1, 2, 3, 4, 5]
+      -> { @array[(0..6).step(2)] }.should.raise(RangeError)
+
+      # end is greater than length with positive steps
+      @array[(1..6).step(2)].should == [1, 3, 5]
+      @array[(2..7).step(2)].should == [2, 4]
+      -> { @array[(2..8).step(2)] }.should.raise(RangeError)
+
+      # begin is greater than length with negative steps
+      @array[(6..1).step(-2)].should == [5, 3, 1]
+      @array[(7..2).step(-2)].should == [5, 3]
+      -> { @array[(8..2).step(-2)] }.should.raise(RangeError)
+    end
+
+    it "has endless range with start outside of array's bounds" do
+      @array[eval("(6..).step(1)")].should == []
+      @array[eval("(7..).step(1)")].should == nil
+
+      @array[eval("(6..).step(2)")].should == []
+      -> { @array[eval("(7..).step(2)")] }.should.raise(RangeError)
+    end
+  end
+
+  it "can accept beginless ranges" do
+    a = [0, 1, 2, 3, 4, 5]
+    a[(..3)].should == [0, 1, 2, 3]
+    a[(...3)].should == [0, 1, 2]
+    a[(..-3)].should == [0, 1, 2, 3]
+    a[(...-3)].should == [0, 1, 2]
+    a[(..0)].should == [0]
+    a[(...0)].should == []
+    a[(..9)].should == [0, 1, 2, 3, 4, 5]
+    a[(...9)].should == [0, 1, 2, 3, 4, 5]
+    a[(..-9)].should == []
+    a[(...-9)].should == []
+  end
+
+  describe "can be sliced with Enumerator::ArithmeticSequence" do
+    it "with infinite/inverted ranges and negative steps" do
+      array = [0, 1, 2, 3, 4, 5]
+      array[(2..).step(-1)].should == [2, 1, 0]
+      array[(2..).step(-2)].should == [2, 0]
+      array[(2..).step(-3)].should == [2]
+      array[(2..).step(-4)].should == [2]
+
+      array[(-3..).step(-1)].should == [3, 2, 1, 0]
+      array[(-3..).step(-2)].should == [3, 1]
+      array[(-3..).step(-3)].should == [3, 0]
+      array[(-3..).step(-4)].should == [3]
+      array[(-3..).step(-5)].should == [3]
+
+      array[(..0).step(-1)].should == [5, 4, 3, 2, 1, 0]
+      array[(..0).step(-2)].should == [5, 3, 1]
+      array[(..0).step(-3)].should == [5, 2]
+      array[(..0).step(-4)].should == [5, 1]
+      array[(..0).step(-5)].should == [5, 0]
+      array[(..0).step(-6)].should == [5]
+      array[(..0).step(-7)].should == [5]
+
+      array[(...0).step(-1)].should == [5, 4, 3, 2, 1]
+      array[(...0).step(-2)].should == [5, 3, 1]
+      array[(...0).step(-3)].should == [5, 2]
+      array[(...0).step(-4)].should == [5, 1]
+      array[(...0).step(-5)].should == [5]
+      array[(...0).step(-6)].should == [5]
+
+      array[(...1).step(-1)].should == [5, 4, 3, 2]
+      array[(...1).step(-2)].should == [5, 3]
+      array[(...1).step(-3)].should == [5, 2]
+      array[(...1).step(-4)].should == [5]
+      array[(...1).step(-5)].should == [5]
+
+      array[(..-5).step(-1)].should == [5, 4, 3, 2, 1]
+      array[(..-5).step(-2)].should == [5, 3, 1]
+      array[(..-5).step(-3)].should == [5, 2]
+      array[(..-5).step(-4)].should == [5, 1]
+      array[(..-5).step(-5)].should == [5]
+      array[(..-5).step(-6)].should == [5]
+
+      array[(...-5).step(-1)].should == [5, 4, 3, 2]
+      array[(...-5).step(-2)].should == [5, 3]
+      array[(...-5).step(-3)].should == [5, 2]
+      array[(...-5).step(-4)].should == [5]
+      array[(...-5).step(-5)].should == [5]
+
+      array[(4..1).step(-1)].should == [4, 3, 2, 1]
+      array[(4..1).step(-2)].should == [4, 2]
+      array[(4..1).step(-3)].should == [4, 1]
+      array[(4..1).step(-4)].should == [4]
+      array[(4..1).step(-5)].should == [4]
+
+      array[(4...1).step(-1)].should == [4, 3, 2]
+      array[(4...1).step(-2)].should == [4, 2]
+      array[(4...1).step(-3)].should == [4]
+      array[(4...1).step(-4)].should == [4]
+
+      array[(-2..1).step(-1)].should == [4, 3, 2, 1]
+      array[(-2..1).step(-2)].should == [4, 2]
+      array[(-2..1).step(-3)].should == [4, 1]
+      array[(-2..1).step(-4)].should == [4]
+      array[(-2..1).step(-5)].should == [4]
+
+      array[(-2...1).step(-1)].should == [4, 3, 2]
+      array[(-2...1).step(-2)].should == [4, 2]
+      array[(-2...1).step(-3)].should == [4]
+      array[(-2...1).step(-4)].should == [4]
+
+      array[(4..-5).step(-1)].should == [4, 3, 2, 1]
+      array[(4..-5).step(-2)].should == [4, 2]
+      array[(4..-5).step(-3)].should == [4, 1]
+      array[(4..-5).step(-4)].should == [4]
+      array[(4..-5).step(-5)].should == [4]
+
+      array[(4...-5).step(-1)].should == [4, 3, 2]
+      array[(4...-5).step(-2)].should == [4, 2]
+      array[(4...-5).step(-3)].should == [4]
+      array[(4...-5).step(-4)].should == [4]
+
+      array[(-2..-5).step(-1)].should == [4, 3, 2, 1]
+      array[(-2..-5).step(-2)].should == [4, 2]
+      array[(-2..-5).step(-3)].should == [4, 1]
+      array[(-2..-5).step(-4)].should == [4]
+      array[(-2..-5).step(-5)].should == [4]
+
+      array[(-2...-5).step(-1)].should == [4, 3, 2]
+      array[(-2...-5).step(-2)].should == [4, 2]
+      array[(-2...-5).step(-3)].should == [4]
+      array[(-2...-5).step(-4)].should == [4]
+    end
+  end
+
+  it "can accept nil...nil ranges" do
+    a = [0, 1, 2, 3, 4, 5]
+    a[eval("(nil...nil)")].should == a
+    a[(...nil)].should == a
+    a[eval("(nil..)")].should == a
+  end
 end
 
 describe "Array.[]" do
@@ -39,12 +892,12 @@ describe "Array.[]" do
     end
 
     it "returns an instance of the subclass" do
-      ArraySpecs::MyArray[1, 2, 3].should be_an_instance_of(ArraySpecs::MyArray)
+      ArraySpecs::MyArray[1, 2, 3].should.instance_of?(ArraySpecs::MyArray)
     end
 
     it "does not call #initialize on the subclass instance" do
       ArraySpecs::MyArray[1, 2, 3].should == [1, 2, 3]
-      ScratchPad.recorded.should be_nil
+      ScratchPad.recorded.should == nil
     end
   end
 end
diff --git a/spec/ruby/core/array/element_set_spec.rb b/spec/ruby/core/array/element_set_spec.rb
index f58f0ffdc4..671e4338de 100644
--- a/spec/ruby/core/array/element_set_spec.rb
+++ b/spec/ruby/core/array/element_set_spec.rb
@@ -36,6 +36,7 @@ describe "Array#[]=" do
     a[3, 2] = ['a', 'b', 'c', 'd']
     a.should == [2, 2, 3, "a", "b", "c", "d", 6]
   end
+
   it "replaces the section defined by [start,length] with the given values" do
     a = [1, 2, 3, 4, 5, 6]
     a[3, 2] = 'a', 'b', 'c', 'd'
@@ -94,8 +95,8 @@ describe "Array#[]=" do
 
   it "checks frozen before attempting to coerce arguments" do
     a = [1,2,3,4].freeze
-    -> {a[:foo] = 1}.should raise_error(frozen_error_class)
-    -> {a[:foo, :bar] = 1}.should raise_error(frozen_error_class)
+    -> {a[:foo] = 1}.should.raise(FrozenError)
+    -> {a[:foo, :bar] = 1}.should.raise(FrozenError)
   end
 
   it "sets elements in the range arguments when passed ranges" do
@@ -169,6 +170,7 @@ describe "Array#[]=" do
     ary[1...1] = []
     ary.should == [1, 2, 3]
   end
+
   it "does nothing if the section defined by range has negative width and the rhs is an empty array" do
     ary = [1, 2, 3, 4, 5]
     ary[1...0] = []
@@ -195,25 +197,25 @@ describe "Array#[]=" do
 
     a[to .. from] = ["x"]
     a.should == [1, "a", "b", "x", "c", 4]
-    -> { a["a" .. "b"] = []  }.should raise_error(TypeError)
-    -> { a[from .. "b"] = [] }.should raise_error(TypeError)
+    -> { a["a" .. "b"] = []  }.should.raise(TypeError)
+    -> { a[from .. "b"] = [] }.should.raise(TypeError)
   end
 
   it "raises an IndexError when passed indexes out of bounds" do
     a = [1, 2, 3, 4]
-    -> { a[-5] = ""      }.should raise_error(IndexError)
-    -> { a[-5, -1] = ""  }.should raise_error(IndexError)
-    -> { a[-5, 0] = ""   }.should raise_error(IndexError)
-    -> { a[-5, 1] = ""   }.should raise_error(IndexError)
-    -> { a[-5, 2] = ""   }.should raise_error(IndexError)
-    -> { a[-5, 10] = ""  }.should raise_error(IndexError)
-
-    -> { a[-5..-5] = ""  }.should raise_error(RangeError)
-    -> { a[-5...-5] = "" }.should raise_error(RangeError)
-    -> { a[-5..-4] = ""  }.should raise_error(RangeError)
-    -> { a[-5...-4] = "" }.should raise_error(RangeError)
-    -> { a[-5..10] = ""  }.should raise_error(RangeError)
-    -> { a[-5...10] = "" }.should raise_error(RangeError)
+    -> { a[-5] = ""      }.should.raise(IndexError)
+    -> { a[-5, -1] = ""  }.should.raise(IndexError)
+    -> { a[-5, 0] = ""   }.should.raise(IndexError)

path: root/benchmark/app_uri.rb

require 'uri'

100_000.times{
  uri = URI.parse('http://www.ruby-lang.org')
  uri.scheme
  uri.host
  uri.port
}