Update to ruby/spec@7f22a0b

62 files changed, 656 insertions, 59 deletions

diff --git a/spec/ruby/core/array/shared/slice.rb b/spec/ruby/core/array/shared/slice.rb
index cf195ad7a4..540a050130 100644
--- a/spec/ruby/core/array/shared/slice.rb
+++ b/spec/ruby/core/array/shared/slice.rb
@@ -743,6 +743,30 @@ describe :array_slice, shared: true do
         @array.send(@method, eval("(-2..-4).step(10)")).should == []
         @array.send(@method, eval("(-2...-4).step(10)")).should == []
       end
+
+      it "has range with bounds outside of array" do
+        # end is equal to array's length
+        @array.send(@method, (0..6).step(1)).should == [0, 1, 2, 3, 4, 5]
+        -> { @array.send(@method, (0..6).step(2)) }.should raise_error(RangeError)
+
+        # end is greater than length with positive steps
+        @array.send(@method, (1..6).step(2)).should == [1, 3, 5]
+        @array.send(@method, (2..7).step(2)).should == [2, 4]
+        -> { @array.send(@method, (2..8).step(2)) }.should raise_error(RangeError)
+
+        # begin is greater than length with negative steps
+        @array.send(@method, (6..1).step(-2)).should == [5, 3, 1]
+        @array.send(@method, (7..2).step(-2)).should == [5, 3]
+        -> { @array.send(@method, (8..2).step(-2)) }.should raise_error(RangeError)
+      end
+
+      it "has endless range with start outside of array's bounds" do
+        @array.send(@method, eval("(6..).step(1)")).should == []
+        @array.send(@method, eval("(7..).step(1)")).should == nil
+
+        @array.send(@method, eval("(6..).step(2)")).should == []
+        -> { @array.send(@method, eval("(7..).step(2)")) }.should raise_error(RangeError)
+      end
     end
   end
 
diff --git a/spec/ruby/core/dir/shared/glob.rb b/spec/ruby/core/dir/shared/glob.rb
index 69fb0f0a01..a38ff8aa68 100644
--- a/spec/ruby/core/dir/shared/glob.rb
+++ b/spec/ruby/core/dir/shared/glob.rb
@@ -55,12 +55,24 @@ describe :dir_glob, shared: true do
     end
   end
 
+  ruby_version_is "3.0"..."3.1" do
+    it "result is sorted with any non false value of sort:" do
+      result = Dir.send(@method, '*', sort: 0)
+      result.should == result.sort
+
+      result = Dir.send(@method, '*', sort: nil)
+      result.should == result.sort
+
+      result = Dir.send(@method, '*', sort: 'false')
+      result.should == result.sort
+    end
+  end
+
   ruby_version_is "3.1" do
-    it "true or false is expected as sort:" do
-      -> {Dir.send(@method, '*', sort: nil)}.should raise_error ArgumentError, /true or false/
-      -> {Dir.send(@method, '*', sort: 0)}.should raise_error ArgumentError, /true or false/
-      -> {Dir.send(@method, '*', sort: "")}.should raise_error ArgumentError, /true or false/
-      -> {Dir.send(@method, '*', sort: Object.new)}.should raise_error ArgumentError, /true or false/
+    it "raises an ArgumentError if sort: is not true or false" do
+      -> { Dir.send(@method, '*', sort: 0) }.should raise_error ArgumentError, /expected true or false/
+      -> { Dir.send(@method, '*', sort: nil) }.should raise_error ArgumentError, /expected true or false/
+      -> { Dir.send(@method, '*', sort: 'false') }.should raise_error ArgumentError, /expected true or false/
     end
   end
 
diff --git a/spec/ruby/core/encoding/compatible_spec.rb b/spec/ruby/core/encoding/compatible_spec.rb
index dc47a6553a..80ecab6155 100644
--- a/spec/ruby/core/encoding/compatible_spec.rb
+++ b/spec/ruby/core/encoding/compatible_spec.rb
@@ -54,7 +54,7 @@ describe "Encoding.compatible? String, String" do
 
     it "returns nil if the second's Encoding is not ASCII compatible" do
       a = "abc".force_encoding("UTF-8")
-      b = "123".force_encoding("UTF-16LE")
+      b = "1234".force_encoding("UTF-16LE")
       Encoding.compatible?(a, b).should be_nil
     end
   end
diff --git a/spec/ruby/core/encoding/converter/putback_spec.rb b/spec/ruby/core/encoding/converter/putback_spec.rb
index 87495eaf3f..c4e0a5da21 100644
--- a/spec/ruby/core/encoding/converter/putback_spec.rb
+++ b/spec/ruby/core/encoding/converter/putback_spec.rb
@@ -34,14 +34,23 @@ describe "Encoding::Converter#putback" do
     @ec.putback.should == ""
   end
 
+  it "returns the problematic bytes for UTF-16LE" do
+    ec = Encoding::Converter.new("utf-16le", "iso-8859-1")
+    src = "\x00\xd8\x61\x00"
+    dst = ""
+    ec.primitive_convert(src, dst).should == :invalid_byte_sequence
+    ec.primitive_errinfo.should == [:invalid_byte_sequence, "UTF-16LE", "UTF-8", "\x00\xD8", "a\x00"]
+    ec.putback.should == "a\x00".force_encoding("utf-16le")
+    ec.putback.should == ""
+  end
+
   it "accepts an integer argument corresponding to the number of bytes to be put back" do
     ec = Encoding::Converter.new("utf-16le", "iso-8859-1")
     src = "\x00\xd8\x61\x00"
     dst = ""
     ec.primitive_convert(src, dst).should == :invalid_byte_sequence
     ec.primitive_errinfo.should == [:invalid_byte_sequence, "UTF-16LE", "UTF-8", "\x00\xD8", "a\x00"]
-    ec.putback(1).should == "\x00".force_encoding("utf-16le")
-    ec.putback.should == "a".force_encoding("utf-16le")
+    ec.putback(2).should == "a\x00".force_encoding("utf-16le")
     ec.putback.should == ""
   end
 end
diff --git a/spec/ruby/core/enumerable/grep_spec.rb b/spec/ruby/core/enumerable/grep_spec.rb
index ac3d3db641..b81075291f 100644
--- a/spec/ruby/core/enumerable/grep_spec.rb
+++ b/spec/ruby/core/enumerable/grep_spec.rb
@@ -65,6 +65,18 @@ describe "Enumerable#grep" do
       ["abc", "def"].grep(/b/).should == ["abc"]
       Regexp.last_match[0].should == "z"
     end
+
+    it "correctly handles non-string elements" do
+      'set last match' =~ /set last (.*)/
+      [:a, 'b', 'z', :c, 42, nil].grep(/[a-d]/).should == [:a, 'b', :c]
+      $1.should == 'match'
+
+      o = Object.new
+      def o.to_str
+        'hello'
+      end
+      [o].grep(/ll/).first.should.equal?(o)
+    end
   end
 
   describe "with a block" do
diff --git a/spec/ruby/core/enumerable/grep_v_spec.rb b/spec/ruby/core/enumerable/grep_v_spec.rb
index 892640efa4..35fde27eb6 100644
--- a/spec/ruby/core/enumerable/grep_v_spec.rb
+++ b/spec/ruby/core/enumerable/grep_v_spec.rb
@@ -45,6 +45,18 @@ describe "Enumerable#grep_v" do
       ["abc", "def"].grep_v(/e/).should == ["abc"]
       Regexp.last_match[0].should == "z"
     end
+
+    it "correctly handles non-string elements" do
+      'set last match' =~ /set last (.*)/
+      [:a, 'b', 'z', :c, 42, nil].grep_v(/[a-d]/).should == ['z', 42, nil]
+      $1.should == 'match'
+
+      o = Object.new
+      def o.to_str
+        'hello'
+      end
+      [o].grep_v(/mm/).first.should.equal?(o)
+    end
   end
 
   describe "without block" do
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/begin_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/begin_spec.rb
index bed30c546d..1837a4f246 100644
--- a/spec/ruby/core/enumerator/arithmetic_sequence/begin_spec.rb
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/begin_spec.rb
@@ -6,4 +6,13 @@ describe "Enumerator::ArithmeticSequence#begin" do
     (1..10).step.begin.should == 1
     (1...10).step.begin.should == 1
   end
+
+  ruby_version_is "2.7" do
+    context "with beginless" do
+      it "returns nil as begin of the sequence" do
+        eval("(..10).step(1)").begin.should == nil
+        eval("(...10).step(1)").begin.should == nil
+      end
+    end
+  end
 end
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/end_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/end_spec.rb
index 29e6e105cf..05429cac3e 100644
--- a/spec/ruby/core/enumerator/arithmetic_sequence/end_spec.rb
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/end_spec.rb
@@ -6,4 +6,11 @@ describe "Enumerator::ArithmeticSequence#end" do
     (1..10).step.end.should == 10
     (1...10).step(17).end.should == 10
   end
+
+  context "with endless" do
+    it "returns nil as end of the sequence" do
+      (1..).step(1).end.should == nil
+      (1...).step(1).end.should == nil
+    end
+  end
 end
diff --git a/spec/ruby/core/exception/errno_spec.rb b/spec/ruby/core/exception/errno_spec.rb
index 095a926e09..a063e522ea 100644
--- a/spec/ruby/core/exception/errno_spec.rb
+++ b/spec/ruby/core/exception/errno_spec.rb
@@ -56,3 +56,12 @@ describe "Errno::ENOTSUP" do
     end
   end
 end
+
+describe "Errno::ENOENT" do
+  it "lets subclasses inherit the default error message" do
+    c = Class.new(Errno::ENOENT)
+    raise c, "custom message"
+  rescue => e
+    e.message.should == "No such file or directory - custom message"
+  end
+end
diff --git a/spec/ruby/core/gc/auto_compact_spec.rb b/spec/ruby/core/gc/auto_compact_spec.rb
index 386725996d..4f9d043171 100644
--- a/spec/ruby/core/gc/auto_compact_spec.rb
+++ b/spec/ruby/core/gc/auto_compact_spec.rb
@@ -12,6 +12,11 @@ ruby_version_is "3.0" do
       original = GC.auto_compact
       begin
         GC.auto_compact = !original
+      rescue NotImplementedError # platform does not support autocompact
+        skip
+      end
+
+      begin
         GC.auto_compact.should == !original
       ensure
         GC.auto_compact = original
diff --git a/spec/ruby/core/gc/measure_total_time_spec.rb b/spec/ruby/core/gc/measure_total_time_spec.rb
new file mode 100644
index 0000000000..05d4598ebc
--- /dev/null
+++ b/spec/ruby/core/gc/measure_total_time_spec.rb
@@ -0,0 +1,19 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "3.1" do
+  describe "GC.measure_total_time" do
+    before :each do
+      @default = GC.measure_total_time
+    end
+
+    after :each do
+      GC.measure_total_time = @default
+    end
+
+    it "can set and get a boolean value" do
+      original = GC.measure_total_time
+      GC.measure_total_time = !original
+      GC.measure_total_time.should == !original
+    end
+  end
+end
diff --git a/spec/ruby/core/gc/stat_spec.rb b/spec/ruby/core/gc/stat_spec.rb
index eb71fd9691..3b43b28a92 100644
--- a/spec/ruby/core/gc/stat_spec.rb
+++ b/spec/ruby/core/gc/stat_spec.rb
@@ -7,6 +7,16 @@ describe "GC.stat" do
     stat.keys.should.include?(:count)
   end
 
+  it "updates the given hash values" do
+    hash = { count: "hello", __other__: "world" }
+    stat = GC.stat(hash)
+
+    stat.should be_kind_of(Hash)
+    stat.should equal hash
+    stat[:count].should be_kind_of(Integer)
+    stat[:__other__].should == "world"
+  end
+
   it "the values are all Integer since rb_gc_stat() returns size_t" do
     GC.stat.values.each { |value| value.should be_kind_of(Integer) }
   end
@@ -41,4 +51,12 @@ describe "GC.stat" do
     GC.stat(:total_allocated_objects).should be_kind_of(Integer)
     GC.stat[:total_allocated_objects].should be_kind_of(Integer)
   end
+
+  it "raises an error if argument is not nil, a symbol, or a hash" do
+    -> { GC.stat(7) }.should raise_error(TypeError, "non-hash or symbol given")
+  end
+
+  it "raises an error if an unknown key is given" do
+    -> { GC.stat(:foo) }.should raise_error(ArgumentError, "unknown key: foo")
+  end
 end
diff --git a/spec/ruby/core/gc/total_time_spec.rb b/spec/ruby/core/gc/total_time_spec.rb
new file mode 100644
index 0000000000..9b4f16e603
--- /dev/null
+++ b/spec/ruby/core/gc/total_time_spec.rb
@@ -0,0 +1,15 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "3.1" do
+  describe "GC.total_time" do
+    it "returns an Integer" do
+      GC.total_time.should be_kind_of(Integer)
+    end
+
+    it "increases as collections are run" do
+      time_before = GC.total_time
+      GC.start
+      GC.total_time.should > time_before
+    end
+  end
+end
diff --git a/spec/ruby/core/integer/plus_spec.rb b/spec/ruby/core/integer/plus_spec.rb
index be626c3305..511a436872 100644
--- a/spec/ruby/core/integer/plus_spec.rb
+++ b/spec/ruby/core/integer/plus_spec.rb
@@ -40,4 +40,19 @@ describe "Integer#+" do
       -> { @bignum + :symbol}.should raise_error(TypeError)
     end
   end
+
+  it "can be redefined" do
+    code = <<~RUBY
+      class Integer
+        alias_method :old_plus, :+
+        def +(other)
+          self - other
+        end
+      end
+      result = 1 + 2
+      Integer.alias_method :+, :old_plus
+      print result
+    RUBY
+    ruby_exe(code).should == "-1"
+  end
 end
diff --git a/spec/ruby/core/kernel/clone_spec.rb b/spec/ruby/core/kernel/clone_spec.rb
index f9daa2badc..38ae1984c0 100644
--- a/spec/ruby/core/kernel/clone_spec.rb
+++ b/spec/ruby/core/kernel/clone_spec.rb
@@ -31,10 +31,10 @@ describe "Kernel#clone" do
   describe "with no arguments" do
     it "copies frozen state from the original" do
       o2 = @obj.clone
+      o2.should_not.frozen?
+
       @obj.freeze
       o3 = @obj.clone
-
-      o2.should_not.frozen?
       o3.should.frozen?
     end
 
@@ -44,6 +44,30 @@ describe "Kernel#clone" do
     end
   end
 
+  describe "with freeze: nil" do
+    ruby_version_is ""..."3.0" do
+      it "raises ArgumentError" do
+        -> { @obj.clone(freeze: nil) }.should raise_error(ArgumentError, /unexpected value for freeze: NilClass/)
+      end
+    end
+
+    ruby_version_is "3.0" do
+      it "copies frozen state from the original, like #clone without arguments" do
+        o2 = @obj.clone(freeze: nil)
+        o2.should_not.frozen?
+
+        @obj.freeze
+        o3 = @obj.clone(freeze: nil)
+        o3.should.frozen?
+      end
+
+      it "copies frozen?" do
+        o = "".freeze.clone(freeze: nil)
+        o.frozen?.should be_true
+      end
+    end
+  end
+
   describe "with freeze: true" do
     it 'makes a frozen copy if the original is frozen' do
       @obj.freeze
@@ -112,6 +136,14 @@ describe "Kernel#clone" do
     end
   end
 
+  describe "with freeze: anything else" do
+    it 'raises ArgumentError when passed not true/false/nil' do
+      -> { @obj.clone(freeze: 1) }.should raise_error(ArgumentError, /unexpected value for freeze: Integer/)
+      -> { @obj.clone(freeze: "") }.should raise_error(ArgumentError, /unexpected value for freeze: String/)
+      -> { @obj.clone(freeze: Object.new) }.should raise_error(ArgumentError, /unexpected value for freeze: Object/)
+    end
+  end
+
   it "copies instance variables" do
     clone = @obj.clone
     clone.one.should == 1
diff --git a/spec/ruby/core/kernel/fixtures/classes.rb b/spec/ruby/core/kernel/fixtures/classes.rb
index 8de1407b92..541a4c075e 100644
--- a/spec/ruby/core/kernel/fixtures/classes.rb
+++ b/spec/ruby/core/kernel/fixtures/classes.rb
@@ -281,9 +281,14 @@ module KernelSpecs
       @two = two
     end
 
-    def initialize_copy(other)
+    def initialize_copy(other, **kw)
       ScratchPad.record object_id
     end
+
+    # define to support calling #clone with optional :freeze keyword argument
+    def initialize_clone(other, **kw)
+      super(other) # to call #initialize_copy
+    end
   end
 
   class Clone
diff --git a/spec/ruby/core/kernel/initialize_clone_spec.rb b/spec/ruby/core/kernel/initialize_clone_spec.rb
new file mode 100644
index 0000000000..2d889f5aad
--- /dev/null
+++ b/spec/ruby/core/kernel/initialize_clone_spec.rb
@@ -0,0 +1,28 @@
+require_relative '../../spec_helper'
+
+describe "Kernel#initialize_clone" do
+  it "is a private instance method" do
+    Kernel.should have_private_instance_method(:initialize_clone)
+  end
+
+  it "returns the receiver" do
+    a = Object.new
+    b = Object.new
+    a.send(:initialize_clone, b).should == a
+  end
+
+  it "calls #initialize_copy" do
+    a = Object.new
+    b = Object.new
+    a.should_receive(:initialize_copy).with(b)
+    a.send(:initialize_clone, b)
+  end
+
+  ruby_version_is "3.0" do
+    it "accepts a :freeze keyword argument for obj.clone(freeze: value)" do
+      a = Object.new
+      b = Object.new
+      a.send(:initialize_clone, b, freeze: true).should == a
+    end
+  end
+end
diff --git a/spec/ruby/core/kernel/initialize_dup_spec.rb b/spec/ruby/core/kernel/initialize_dup_spec.rb
new file mode 100644
index 0000000000..6dff34b7ad
--- /dev/null
+++ b/spec/ruby/core/kernel/initialize_dup_spec.rb
@@ -0,0 +1,20 @@
+require_relative '../../spec_helper'
+
+describe "Kernel#initialize_dup" do
+  it "is a private instance method" do
+    Kernel.should have_private_instance_method(:initialize_dup)
+  end
+
+  it "returns the receiver" do
+    a = Object.new
+    b = Object.new
+    a.send(:initialize_dup, b).should == a
+  end
+
+  it "calls #initialize_copy" do
+    a = Object.new
+    b = Object.new
+    a.should_receive(:initialize_copy).with(b)
+    a.send(:initialize_dup, b)
+  end
+end
diff --git a/spec/ruby/core/kernel/instance_variables_spec.rb b/spec/ruby/core/kernel/instance_variables_spec.rb
index 831f0662a2..677d8bb7b2 100644
--- a/spec/ruby/core/kernel/instance_variables_spec.rb
+++ b/spec/ruby/core/kernel/instance_variables_spec.rb
@@ -25,5 +25,16 @@ describe "Kernel#instance_variables" do
       a.instance_variable_set("@test", 1)
       a.instance_variables.should == [:@test]
     end
+
+    it "returns the instances variables in the order declared" do
+      c = Class.new do
+        def initialize
+          @c = 1
+          @a = 2
+          @b = 3
+        end
+      end
+      c.new.instance_variables.should == [:@c, :@a, :@b]
+    end
   end
 end
diff --git a/spec/ruby/core/kernel/print_spec.rb b/spec/ruby/core/kernel/print_spec.rb
index c8c4453d1e..7e7c9b822d 100644
--- a/spec/ruby/core/kernel/print_spec.rb
+++ b/spec/ruby/core/kernel/print_spec.rb
@@ -5,6 +5,18 @@ describe "Kernel#print" do
   it "is a private method" do
     Kernel.should have_private_instance_method(:print)
   end
+
+  it "delegates to $stdout" do
+    -> { print :arg }.should output("arg")
+  end
+
+  it "prints $_ when no arguments are given" do
+    orig_value = $_
+    $_ = 'foo'
+    -> { print }.should output("foo")
+  ensure
+    $_ = orig_value
+  end
 end
 
 describe "Kernel.print" do
diff --git a/spec/ruby/core/kernel/warn_spec.rb b/spec/ruby/core/kernel/warn_spec.rb
index 511e741f32..7df6fa72d1 100644
--- a/spec/ruby/core/kernel/warn_spec.rb
+++ b/spec/ruby/core/kernel/warn_spec.rb
@@ -212,6 +212,70 @@ describe "Kernel#warn" do
     -> { warn('foo', **h) }.should complain("foo\n")
   end
 
+  ruby_version_is '3.0' do
+    it "calls Warning.warn without keyword arguments if Warning.warn does not accept keyword arguments" do
+      verbose = $VERBOSE
+      $VERBOSE = false
+      class << Warning
+        alias_method :_warn, :warn
+        def warn(message)
+          ScratchPad.record(message)
+        end
+      end
+
+      begin
+        ScratchPad.clear
+        Kernel.warn("Chunky bacon!")
+        ScratchPad.recorded.should == "Chunky bacon!\n"
+
+        Kernel.warn("Deprecated bacon!", category: :deprecated)
+        ScratchPad.recorded.should == "Deprecated bacon!\n"
+      ensure
+        class << Warning
+          remove_method :warn
+          alias_method :warn, :_warn
+          remove_method :_warn
+        end
+        $VERBOSE = verbose
+      end
+    end
+
+    it "calls Warning.warn with category: nil if Warning.warn accepts keyword arguments" do
+      Warning.should_receive(:warn).with("Chunky bacon!\n", category: nil)
+      verbose = $VERBOSE
+      $VERBOSE = false
+      begin
+        Kernel.warn("Chunky bacon!")
+      ensure
+        $VERBOSE = verbose
+      end
+    end
+
+    it "calls Warning.warn with given category keyword converted to a symbol" do
+      Warning.should_receive(:warn).with("Chunky bacon!\n", category: :deprecated)
+      verbose = $VERBOSE
+      $VERBOSE = false
+      begin
+        Kernel.warn("Chunky bacon!", category: 'deprecated')
+      ensure
+        $VERBOSE = verbose
+      end
+    end
+  end
+
+  ruby_version_is ''...'3.0' do
+    it "calls Warning.warn with no keyword arguments" do
+      Warning.should_receive(:warn).with("Chunky bacon!\n")
+      verbose = $VERBOSE
+      $VERBOSE = false
+      begin
+        Kernel.warn("Chunky bacon!")
+      ensure
+        $VERBOSE = verbose
+      end
+    end
+  end
+
   it "does not call Warning.warn if self is the Warning module" do
     # RubyGems redefines Kernel#warn so we need to use a subprocess and disable RubyGems here
     code = <<-RUBY
diff --git a/spec/ruby/core/matchdata/captures_spec.rb b/spec/ruby/core/matchdata/captures_spec.rb
index 8c0d2978b7..58d4620709 100644
--- a/spec/ruby/core/matchdata/captures_spec.rb
+++ b/spec/ruby/core/matchdata/captures_spec.rb
@@ -1,7 +1,15 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "MatchData#captures" do
   it "returns an array of the match captures" do
     /(.)(.)(\d+)(\d)/.match("THX1138.").captures.should == ["H","X","113","8"]
   end
+
+  ruby_version_is "3.0" do
+    it "returns instances of String when given a String subclass" do
+      str = MatchDataSpecs::MyString.new("THX1138: The Movie")
+      /(.)(.)(\d+)(\d)/.match(str).captures.each { |c| c.should be_an_instance_of(String) }
+    end
+  end
 end
diff --git a/spec/ruby/core/matchdata/element_reference_spec.rb b/spec/ruby/core/matchdata/element_reference_spec.rb
index 26550ac94d..3b976cb1c4 100644
--- a/spec/ruby/core/matchdata/element_reference_spec.rb
+++ b/spec/ruby/core/matchdata/element_reference_spec.rb
@@ -1,4 +1,5 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "MatchData#[]" do
   it "acts as normal array indexing [index]" do
@@ -20,6 +21,13 @@ describe "MatchData#[]" do
   it "supports ranges [start..end]" do
     /(.)(.)(\d+)(\d)/.match("THX1138.")[1..3].should == %w|H X 113|
   end
+
+  ruby_version_is "3.0" do
+    it "returns instances of String when given a String subclass" do
+      str = MatchDataSpecs::MyString.new("THX1138.")
+      /(.)(.)(\d+)(\d)/.match(str)[0..-1].each { |m| m.should be_an_instance_of(String) }
+    end
+  end
 end
 
 describe "MatchData#[Symbol]" do
diff --git a/spec/ruby/core/matchdata/fixtures/classes.rb b/spec/ruby/core/matchdata/fixtures/classes.rb
new file mode 100644
index 0000000000..54795636e5
--- /dev/null
+++ b/spec/ruby/core/matchdata/fixtures/classes.rb
@@ -0,0 +1,3 @@
+module MatchDataSpecs
+  class MyString < String; end
+end
diff --git a/spec/ruby/core/matchdata/post_match_spec.rb b/spec/ruby/core/matchdata/post_match_spec.rb
index 4ae51f107e..1a4ca0a83f 100644
--- a/spec/ruby/core/matchdata/post_match_spec.rb
+++ b/spec/ruby/core/matchdata/post_match_spec.rb
@@ -1,4 +1,5 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "MatchData#post_match" do
   it "returns the string after the match equiv. special var $'" do
@@ -33,4 +34,11 @@ describe "MatchData#post_match" do
     str = "abc".force_encoding Encoding::ISO_8859_1
     str.match(/c/).post_match.encoding.should equal(Encoding::ISO_8859_1)
   end
+
+  ruby_version_is "3.0" do
+    it "returns an instance of String when given a String subclass" do
+      str = MatchDataSpecs::MyString.new("THX1138: The Movie")
+      /(.)(.)(\d+)(\d)/.match(str).post_match.should be_an_instance_of(String)
+    end
+  end
 end
diff --git a/spec/ruby/core/matchdata/pre_match_spec.rb b/spec/ruby/core/matchdata/pre_match_spec.rb
index 824612c84c..9b50336c7d 100644
--- a/spec/ruby/core/matchdata/pre_match_spec.rb
+++ b/spec/ruby/core/matchdata/pre_match_spec.rb
@@ -1,4 +1,5 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "MatchData#pre_match" do
   it "returns the string before the match, equiv. special var $`" do
@@ -33,4 +34,11 @@ describe "MatchData#pre_match" do
     str = "abc".force_encoding Encoding::ISO_8859_1
     str.match(/a/).pre_match.encoding.should equal(Encoding::ISO_8859_1)
   end
+
+  ruby_version_is "3.0" do
+    it "returns an instance of String when given a String subclass" do
+      str = MatchDataSpecs::MyString.new("THX1138: The Movie")
+      /(.)(.)(\d+)(\d)/.match(str).pre_match.should be_an_instance_of(String)
+    end
+  end
 end
diff --git a/spec/ruby/core/matchdata/to_a_spec.rb b/spec/ruby/core/matchdata/to_a_spec.rb
index 6231d096fb..50f5a161a5 100644
--- a/spec/ruby/core/matchdata/to_a_spec.rb
+++ b/spec/ruby/core/matchdata/to_a_spec.rb
@@ -1,7 +1,15 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "MatchData#to_a" do
   it "returns an array of matches" do
     /(.)(.)(\d+)(\d)/.match("THX1138.").to_a.should == ["HX1138", "H", "X", "113", "8"]
   end
+
+  ruby_version_is "3.0" do
+    it "returns instances of String when given a String subclass" do
+      str = MatchDataSpecs::MyString.new("THX1138.")
+      /(.)(.)(\d+)(\d)/.match(str)[0..-1].to_a.each { |m| m.should be_an_instance_of(String) }
+    end
+  end
 end
diff --git a/spec/ruby/core/matchdata/to_s_spec.rb b/spec/ruby/core/matchdata/to_s_spec.rb
index 9e213bb342..aab0955ae1 100644
--- a/spec/ruby/core/matchdata/to_s_spec.rb
+++ b/spec/ruby/core/matchdata/to_s_spec.rb
@@ -1,7 +1,15 @@
 require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 describe "MatchData#to_s" do
   it "returns the entire matched string" do
     /(.)(.)(\d+)(\d)/.match("THX1138.").to_s.should == "HX1138"
   end
+
+  ruby_version_is "3.0" do
+    it "returns an instance of String when given a String subclass" do
+      str = MatchDataSpecs::MyString.new("THX1138.")
+      /(.)(.)(\d+)(\d)/.match(str).to_s.should be_an_instance_of(String)
+    end
+  end
 end
diff --git a/spec/ruby/core/numeric/clone_spec.rb b/spec/ruby/core/numeric/clone_spec.rb
index e3bf0a9e7c..c3b06ca0c9 100644
--- a/spec/ruby/core/numeric/clone_spec.rb
+++ b/spec/ruby/core/numeric/clone_spec.rb
@@ -22,4 +22,11 @@ describe "Numeric#clone" do
   it "raises ArgumentError if passed freeze: false" do
     -> { 1.clone(freeze: false) }.should raise_error(ArgumentError, /can't unfreeze/)
   end
+
+  ruby_version_is "3.0" do
+    it "does not change frozen status if passed freeze: nil" do
+      value = 1
+      value.clone(freeze: nil).should equal(value)
+    end
+  end
 end
diff --git a/spec/ruby/core/numeric/quo_spec.rb b/spec/ruby/core/numeric/quo_spec.rb
index 5c952b11a9..b4a23fd476 100644
--- a/spec/ruby/core/numeric/quo_spec.rb
+++ b/spec/ruby/core/numeric/quo_spec.rb
@@ -52,4 +52,13 @@ describe "Numeric#quo" do
 
     obj.quo(19).should == 1.quo(20)
   end
+
+  it "raises a ZeroDivisionError if the given argument is zero and not a Float" do
+    -> { 1.quo(0) }.should raise_error(ZeroDivisionError)
+  end
+
+  it "returns infinity if the given argument is zero and is a Float" do
+    (1.quo(0.0)).to_s.should == 'Infinity'
+    (-1.quo(0.0)).to_s.should == '-Infinity'
+  end
 end
diff --git a/spec/ruby/core/range/step_spec.rb b/spec/ruby/core/range/step_spec.rb
index 624fa71f5f..4c69073854 100644
--- a/spec/ruby/core/range/step_spec.rb
+++ b/spec/ruby/core/range/step_spec.rb
@@ -481,6 +481,32 @@ describe "Range#step" do
           end
         end
 
+        ruby_version_is "2.7" do
+          context "when begin is not defined and end is numeric" do
+            it "returns an instance of Enumerator::ArithmeticSequence" do
+              eval("(..10)").step.class.should == Enumerator::ArithmeticSequence
+            end
+          end
+        end
+
+        context "when range is endless" do
+          it "returns an instance of Enumerator::ArithmeticSequence when begin is numeric" do
+            (1..).step.class.should == Enumerator::ArithmeticSequence
+          end
+
+          it "returns an instance of Enumerator when begin is not numeric" do
+            ("a"..).step.class.should == Enumerator
+          end
+        end
+
+        ruby_version_is "2.7" do
+          context "when range is beginless and endless" do
+            it "returns an instance of Enumerator" do
+              Range.new(nil, nil).step.class.should == Enumerator
+            end
+          end
+        end
+
         context "when begin and end are not numerics" do
           it "returns an instance of Enumerator" do
             ("a".."z").step.class.should == Enumerator
diff --git a/spec/ruby/core/string/each_grapheme_cluster_spec.rb b/spec/ruby/core/string/each_grapheme_cluster_spec.rb
index 632f2337f1..b45d89ecb0 100644
--- a/spec/ruby/core/string/each_grapheme_cluster_spec.rb
+++ b/spec/ruby/core/string/each_grapheme_cluster_spec.rb
@@ -6,4 +6,12 @@ describe "String#each_grapheme_cluster" do
   it_behaves_like :string_chars, :each_grapheme_cluster
   it_behaves_like :string_grapheme_clusters, :each_grapheme_cluster
   it_behaves_like :string_each_char_without_block, :each_grapheme_cluster
+
+  ruby_version_is '3.0' do
+    it "yields String instances for subclasses" do
+      a = []
+      StringSpecs::MyString.new("abc").each_grapheme_cluster { |s| a << s.class }
+      a.should == [String, String, String]
+    end
+  end
 end
diff --git a/spec/ruby/core/string/force_encoding_spec.rb b/spec/ruby/core/string/force_encoding_spec.rb
index 2fe5f79c0f..f37aaf9eb4 100644
--- a/spec/ruby/core/string/force_encoding_spec.rb
+++ b/spec/ruby/core/string/force_encoding_spec.rb
@@ -60,7 +60,7 @@ describe "String#force_encoding" do
   end
 
   it "does not transcode self" do
-    str = "\u{8612}"
+    str = "é"
     str.dup.force_encoding('utf-16le').should_not == str.encode('utf-16le')
   end
 
diff --git a/spec/ruby/core/string/scan_spec.rb b/spec/ruby/core/string/scan_spec.rb
index 024e97022a..5f86dbbecc 100644
--- a/spec/ruby/core/string/scan_spec.rb
+++ b/spec/ruby/core/string/scan_spec.rb
@@ -198,4 +198,12 @@ describe "String#scan with pattern and block" do
       third.should == 'c';
     end
   end
+
+  ruby_version_is '3.0' do
+    it "yields String instances for subclasses" do
+      a = []
+      StringSpecs::MyString.new("abc").scan(/./) { |s| a << s.class }
+      a.should == [String, String, String]
+    end
+  end
 end
diff --git a/spec/ruby/core/string/scrub_spec.rb b/spec/ruby/core/string/scrub_spec.rb
index 4da44a7992..3137399291 100644
--- a/spec/ruby/core/string/scrub_spec.rb
+++ b/spec/ruby/core/string/scrub_spec.rb
@@ -56,7 +56,9 @@ describe "String#scrub with a custom replacement" do
   it "replaces invalid byte sequences in frozen strings" do
     x81 = [0x81].pack('C').force_encoding('utf-8')
     (-"abc\u3042#{x81}").scrub("*").should == "abc\u3042*"
-    utf16_str = ("abc".encode('UTF-16LE').bytes + [0x81]).pack('c*').force_encoding('UTF-16LE')
+
+    leading_surrogate = [0x00, 0xD8]
+    utf16_str = ("abc".encode('UTF-16LE').bytes + leading_surrogate).pack('c*').force_encoding('UTF-16LE')
     (-(utf16_str)).scrub("*".encode('UTF-16LE')).should == "abc*".encode('UTF-16LE')
   end
 
diff --git a/spec/ruby/core/string/shared/eql.rb b/spec/ruby/core/string/shared/eql.rb
index 85b861f4f1..b57d6895ff 100644
--- a/spec/ruby/core/string/shared/eql.rb
+++ b/spec/ruby/core/string/shared/eql.rb
@@ -21,7 +21,7 @@ describe :string_eql_value, shared: true do
   end
 
   it "considers encoding compatibility" do
-    "hello".force_encoding("utf-8").send(@method, "hello".force_encoding("utf-32le")).should be_false
+    "abcd".force_encoding("utf-8").send(@method, "abcd".force_encoding("utf-32le")).should be_false
   end
 
   it "ignores subclass differences" do
diff --git a/spec/ruby/core/string/shared/length.rb b/spec/ruby/core/string/shared/length.rb
index b9eae5170f..e931961455 100644
--- a/spec/ruby/core/string/shared/length.rb
+++ b/spec/ruby/core/string/shared/length.rb
@@ -36,4 +36,20 @@ describe :string_length, shared: true do
     concat.force_encoding(Encoding::ASCII_8BIT)
     concat.size.should == 4
   end
+
+  it "adds 1 for every invalid byte in UTF-8" do
+    "\xF4\x90\x80\x80".size.should == 4
+    "a\xF4\x90\x80\x80b".size.should == 6
+    "é\xF4\x90\x80\x80è".size.should == 6
+  end
+
+  it "adds 1 (and not 2) for a incomplete surrogate in UTF-16" do
+    "\x00\xd8".force_encoding("UTF-16LE").size.should == 1
+    "\xd8\x00".force_encoding("UTF-16BE").size.should == 1
+  end
+
+  it "adds 1 for a broken sequence in UTF-32" do
+    "\x04\x03\x02\x01".force_encoding("UTF-32LE").size.should == 1
+    "\x01\x02\x03\x04".force_encoding("UTF-32BE").size.should == 1
+  end
 end
diff --git a/spec/ruby/core/string/valid_encoding_spec.rb b/spec/ruby/core/string/valid_encoding_spec.rb
index d5bf31710f..be7cef7a8e 100644
--- a/spec/ruby/core/string/valid_encoding_spec.rb
+++ b/spec/ruby/core/string/valid_encoding_spec.rb
@@ -43,10 +43,10 @@ describe "String#valid_encoding?" do
     str.force_encoding('KOI8-R').valid_encoding?.should be_true
     str.force_encoding('KOI8-U').valid_encoding?.should be_true
     str.force_encoding('Shift_JIS').valid_encoding?.should be_false
-    str.force_encoding('UTF-16BE').valid_encoding?.should be_false
-    str.force_encoding('UTF-16LE').valid_encoding?.should be_false
-    str.force_encoding('UTF-32BE').valid_encoding?.should be_false
-    str.force_encoding('UTF-32LE').valid_encoding?.should be_false
+    "\xD8\x00".force_encoding('UTF-16BE').valid_encoding?.should be_false
+    "\x00\xD8".force_encoding('UTF-16LE').valid_encoding?.should be_false
+    "\x04\x03\x02\x01".force_encoding('UTF-32BE').valid_encoding?.should be_false
+    "\x01\x02\x03\x04".force_encoding('UTF-32LE').valid_encoding?.should be_false
     str.force_encoding('Windows-1251').valid_encoding?.should be_true
     str.force_encoding('IBM437').valid_encoding?.should be_true
     str.force_encoding('IBM737').valid_encoding?.should be_true
diff --git a/spec/ruby/core/warning/element_reference_spec.rb b/spec/ruby/core/warning/element_reference_spec.rb
index a346cf535b..f51cc87de5 100644
--- a/spec/ruby/core/warning/element_reference_spec.rb
+++ b/spec/ruby/core/warning/element_reference_spec.rb
@@ -12,5 +12,11 @@ ruby_version_is '2.7' do
     it "raises for unknown category" do
       -> { Warning[:noop] }.should raise_error(ArgumentError, /unknown category: noop/)
     end
+
+    it "raises for non-Symbol category" do
+      -> { Warning[42] }.should raise_error(TypeError)
+      -> { Warning[false] }.should raise_error(TypeError)
+      -> { Warning["noop"] }.should raise_error(TypeError)
+    end
   end
 end
diff --git a/spec/ruby/core/warning/element_set_spec.rb b/spec/ruby/core/warning/element_set_spec.rb
index 3b0ea45c9b..611060fb3a 100644
--- a/spec/ruby/core/warning/element_set_spec.rb
+++ b/spec/ruby/core/warning/element_set_spec.rb
@@ -27,5 +27,11 @@ ruby_version_is '2.7' do
     it "raises for unknown category" do
       -> { Warning[:noop] = false }.should raise_error(ArgumentError, /unknown category: noop/)
     end
+
+    it "raises for non-Symbol category" do
+      -> { Warning[42] = false }.should raise_error(TypeError)
+      -> { Warning[false] = false }.should raise_error(TypeError)
+      -> { Warning["noop"] = false }.should raise_error(TypeError)
+    end
   end
 end
diff --git a/spec/ruby/core/warning/warn_spec.rb b/spec/ruby/core/warning/warn_spec.rb
index 2ded6a109d..5ccff3aa2b 100644
--- a/spec/ruby/core/warning/warn_spec.rb
+++ b/spec/ruby/core/warning/warn_spec.rb
@@ -51,7 +51,6 @@ describe "Warning.warn" do
     end
   end
 
-
   ruby_version_is '3.0' do
     it "is called by Kernel.warn with nil category keyword" do
       Warning.should_receive(:warn).with("Chunky bacon!\n", category: nil)
@@ -69,7 +68,7 @@ describe "Warning.warn" do
       verbose = $VERBOSE
       $VERBOSE = false
       begin
-        Kernel.warn("Chunky bacon!", category: 'deprecated')
+        Kernel.warn("Chunky bacon!", category: "deprecated")
       ensure
         $VERBOSE = verbose
       end
diff --git a/spec/ruby/language/class_variable_spec.rb b/spec/ruby/language/class_variable_spec.rb
index 9a4b36e82b..f98deaa081 100644
--- a/spec/ruby/language/class_variable_spec.rb
+++ b/spec/ruby/language/class_variable_spec.rb
@@ -94,6 +94,12 @@ ruby_version_is "3.0" do
       }.should raise_error(RuntimeError, 'class variable access from toplevel')
     end
 
+    it "does not raise an error when checking if defined from the toplevel scope" do
+      -> {
+        eval "defined?(@@cvar_toplevel1)"
+      }.should_not raise_error
+    end
+
     it "raises a RuntimeError when a class variable is overtaken in an ancestor class" do
       parent = Class.new()
       subclass = Class.new(parent)
diff --git a/spec/ruby/language/regexp/encoding_spec.rb b/spec/ruby/language/regexp/encoding_spec.rb
index 8e2a294b95..febc3fdb37 100644
--- a/spec/ruby/language/regexp/encoding_spec.rb
+++ b/spec/ruby/language/regexp/encoding_spec.rb
@@ -38,6 +38,10 @@ describe "Regexps with encoding modifiers" do
     /#{/./}/n.match("\303\251").to_a.should == ["\303"]
   end
 
+  it "warns when using /n with a match string with non-ASCII characters and an encoding other than ASCII-8BIT" do
+    -> { /./n.match("\303\251".force_encoding('utf-8')) }.should complain(%r{historical binary regexp match /.../n against UTF-8 string})
+  end
+
   it 'uses US-ASCII as /n encoding if all chars are 7-bit' do
     /./n.encoding.should == Encoding::US_ASCII
   end
@@ -117,6 +121,19 @@ describe "Regexps with encoding modifiers" do
     -> { /\A[[:space:]]*\z/ =~ " ".encode("UTF-16LE") }.should raise_error(Encoding::CompatibilityError)
   end
 
+  it "raises Encoding::CompatibilityError when the regexp has a fixed, non-ASCII-compatible encoding" do
+    -> { Regexp.new("".force_encoding("UTF-16LE"), Regexp::FIXEDENCODING) =~ " ".encode("UTF-8") }.should raise_error(Encoding::CompatibilityError)
+  end
+
+  it "raises Encoding::CompatibilityError when the regexp has a fixed encoding and the match string has non-ASCII characters" do
+    -> { Regexp.new("".force_encoding("US-ASCII"), Regexp::FIXEDENCODING) =~ "\303\251".force_encoding('UTF-8') }.should raise_error(Encoding::CompatibilityError)
+  end
+
+  it "raises ArgumentError when trying to match a broken String" do
+    s = "\x80".force_encoding('UTF-8')
+    -> { s =~ /./ }.should raise_error(ArgumentError, "invalid byte sequence in UTF-8")
+  end
+
   it "computes the Regexp Encoding for each interpolated Regexp instance" do
     make_regexp = -> str { /#{str}/ }
 
diff --git a/spec/ruby/library/fiber/resume_spec.rb b/spec/ruby/library/fiber/resume_spec.rb
index 39d14bdda0..8b7c104a6f 100644
--- a/spec/ruby/library/fiber/resume_spec.rb
+++ b/spec/ruby/library/fiber/resume_spec.rb
@@ -10,6 +10,12 @@ describe "Fiber#resume" do
       fiber2.resume
       -> { fiber2.resume }.should raise_error(FiberError)
     end
+
+    it "raises a FiberError if the Fiber attempts to resume a resuming fiber" do
+      root_fiber = Fiber.current
+      fiber1 = Fiber.new { root_fiber.resume }
+      -> { fiber1.resume }.should raise_error(FiberError, /double resume/)
+    end
   end
 
   ruby_version_is '3.0' do
@@ -19,5 +25,11 @@ describe "Fiber#resume" do
       fiber2.resume.should == 10
       fiber2.resume.should == 20
     end
+
+    it "raises a FiberError if the Fiber attempts to resume a resuming fiber" do
+      root_fiber = Fiber.current
+      fiber1 = Fiber.new { root_fiber.resume }
+      -> { fiber1.resume }.should raise_error(FiberError, /attempt to resume a resuming fiber/)
+    end
   end
 end
diff --git a/spec/ruby/library/rexml/element/each_element_with_attribute_spec.rb b/spec/ruby/library/rexml/element/each_element_with_attribute_spec.rb
index f2d779e577..dcc6dbbf17 100644
--- a/spec/ruby/library/rexml/element/each_element_with_attribute_spec.rb
+++ b/spec/ruby/library/rexml/element/each_element_with_attribute_spec.rb
@@ -12,23 +12,23 @@ ruby_version_is ''...'3.0' do
       @son.attributes["name"] = "Fred"
       @document.root << @father
       @document.root << @son
-      @childs = []
+      @children = []
     end
 
-    it "returns childs with attribute" do
-      @document.each_element_with_attribute("name") { |elem| @childs << elem }
-      @childs[0].should == @father
-      @childs[1].should == @son
+    it "returns children with attribute" do
+      @document.each_element_with_attribute("name") { |elem| @children << elem }
+      @children[0].should == @father
+      @children[1].should == @son
     end
 
     it "takes attribute value as second argument" do
       @document.each_element_with_attribute("name", "Fred"){ |elem| elem.should == @son }
     end
 
-    it "takes max number of childs as third argument" do
-      @document.each_element_with_attribute("name", nil, 1) { |elem| @childs << elem }
-      @childs.size.should == 1
-      @childs[0].should == @father
+    it "takes max number of children as third argument" do
+      @document.each_element_with_attribute("name", nil, 1) { |elem| @children << elem }
+      @children.size.should == 1
+      @children[0].should == @father
     end
 
     it "takes XPath filter as fourth argument" do
diff --git a/spec/ruby/library/rexml/element/each_element_with_text_spec.rb b/spec/ruby/library/rexml/element/each_element_with_text_spec.rb
index 8f9d062c99..a4a200d237 100644
--- a/spec/ruby/library/rexml/element/each_element_with_text_spec.rb
+++ b/spec/ruby/library/rexml/element/each_element_with_text_spec.rb
@@ -16,10 +16,10 @@ ruby_version_is ''...'3.0' do
       @document.root << @joe
       @document.root << @fred
       @document.root << @another
-      @childs = []
+      @children = []
     end
 
-    it "returns childs with text" do
+    it "returns children with text" do
       @document.each_element_with_text("Joe"){|c| c.should == @joe}
     end
 
diff --git a/spec/ruby/library/rexml/element/has_text_spec.rb b/spec/ruby/library/rexml/element/has_text_spec.rb
index de19fe0763..206c167ae6 100644
--- a/spec/ruby/library/rexml/element/has_text_spec.rb
+++ b/spec/ruby/library/rexml/element/has_text_spec.rb
@@ -11,7 +11,7 @@ ruby_version_is ''...'3.0' do
       e.has_text?.should be_true
     end
 
-    it "returns false if it has no Text childs" do
+    it "returns false if it has no Text children" do
       e = REXML::Element.new("Person")
       e.has_text?.should be_false
     end
diff --git a/spec/ruby/library/rexml/node/parent_spec.rb b/spec/ruby/library/rexml/node/parent_spec.rb
index 07425e8f36..43c3a747e0 100644
--- a/spec/ruby/library/rexml/node/parent_spec.rb
+++ b/spec/ruby/library/rexml/node/parent_spec.rb
@@ -14,7 +14,7 @@ ruby_version_is ''...'3.0' do
       e.should.parent?
     end
 
-    # This includes attributes, CDatas and declarations.
+    # This includes attributes, CData and declarations.
     it "returns false for Texts" do
       e = REXML::Text.new("foo")
       e.should_not.parent?
diff --git a/spec/ruby/library/rexml/shared/elements_to_a.rb b/spec/ruby/library/rexml/shared/elements_to_a.rb
index 388250d8b3..b7169f0b2e 100644
--- a/spec/ruby/library/rexml/shared/elements_to_a.rb
+++ b/spec/ruby/library/rexml/shared/elements_to_a.rb
@@ -19,7 +19,7 @@ describe :rexml_elements_to_a, shared: true do
   # always needs the first param (even if it's nil).
   # A patch was submitted:
   # http://rubyforge.org/tracker/index.php?func=detail&aid=19354&group_id=426&atid=1698
-  it "returns all childs if xpath is nil" do
+  it "returns all children if xpath is nil" do
     @e.elements.send(@method).should == [@first, @second]
   end
 
diff --git a/spec/ruby/library/stringio/ungetbyte_spec.rb b/spec/ruby/library/stringio/ungetbyte_spec.rb
index 2f082acbf6..87b27b837e 100644
--- a/spec/ruby/library/stringio/ungetbyte_spec.rb
+++ b/spec/ruby/library/stringio/ungetbyte_spec.rb
@@ -12,7 +12,7 @@ describe "StringIO#ungetbyte" do
     io.string.should == 'Shis is a simple string.'
   end
 
-  it "ungets a single byte from a string in the middle of a multibyte characte" do
+  it "ungets a single byte from a string in the middle of a multibyte character" do
     str = "\u01a9"
     io = StringIO.new(str)
     b = io.getbyte
diff --git a/spec/ruby/library/stringscanner/check_until_spec.rb b/spec/ruby/library/stringscanner/check_until_spec.rb
index e92ae5a2e9..ad222fd76b 100644
--- a/spec/ruby/library/stringscanner/check_until_spec.rb
+++ b/spec/ruby/library/stringscanner/check_until_spec.rb
@@ -12,4 +12,10 @@ describe "StringScanner#check_until" do
     @s.matched.should == "a"
     @s.check_until(/test/).should == "This is a test"
   end
+
+  it "raises TypeError if given a String" do
+    -> {
+      @s.check_until('T')
+    }.should raise_error(TypeError, 'wrong argument type String (expected Regexp)')
+  end
 end
diff --git a/spec/ruby/library/stringscanner/exist_spec.rb b/spec/ruby/library/stringscanner/exist_spec.rb
index beafadc07b..ff860a0d3e 100644
--- a/spec/ruby/library/stringscanner/exist_spec.rb
+++ b/spec/ruby/library/stringscanner/exist_spec.rb
@@ -21,4 +21,10 @@ describe "StringScanner#exist?" do
     @s.scan(/This is/)
     @s.exist?(/i/).should == nil
   end
+
+  it "raises TypeError if given a String" do
+    -> {
+      @s.exist?('T')
+    }.should raise_error(TypeError, 'wrong argument type String (expected Regexp)')
+  end
 end
diff --git a/spec/ruby/library/stringscanner/matched_size_spec.rb b/spec/ruby/library/stringscanner/matched_size_spec.rb
index a36bd3aafe..d9c338a07e 100644
--- a/spec/ruby/library/stringscanner/matched_size_spec.rb
+++ b/spec/ruby/library/stringscanner/matched_size_spec.rb
@@ -1,7 +1,24 @@
 require_relative '../../spec_helper'
-require_relative 'shared/matched_size'
 require 'strscan'
 
 describe "StringScanner#matched_size" do
-  it_behaves_like :strscan_matched_size, :matched_size
+  before :each do
+    @s = StringScanner.new("This is a test")
+  end
+
+  it "returns the size of the most recent match" do
+    @s.check(/This/)
+    @s.matched_size.should == 4
+    @s.matched_size.should == 4
+    @s.scan(//)
+    @s.matched_size.should == 0
+  end
+
+  it "returns nil if there was no recent match" do
+    @s.matched_size.should == nil
+    @s.check(/\d+/)
+    @s.matched_size.should == nil
+    @s.terminate
+    @s.matched_size.should == nil
+  end
 end
diff --git a/spec/ruby/library/stringscanner/scan_until_spec.rb b/spec/ruby/library/stringscanner/scan_until_spec.rb
index 94239db50e..6b7782572d 100644
--- a/spec/ruby/library/stringscanner/scan_until_spec.rb
+++ b/spec/ruby/library/stringscanner/scan_until_spec.rb
@@ -20,4 +20,10 @@ describe "StringScanner#scan_until" do
     @s.scan(/T/)
     @s.scan_until(/^h/).should == "h"
   end
+
+  it "raises TypeError if given a String" do
+    -> {
+      @s.scan_until('T')
+    }.should raise_error(TypeError, 'wrong argument type String (expected Regexp)')
+  end
 end
diff --git a/spec/ruby/library/stringscanner/search_full_spec.rb b/spec/ruby/library/stringscanner/search_full_spec.rb
index da9067e012..7d2a714fa5 100644
--- a/spec/ruby/library/stringscanner/search_full_spec.rb
+++ b/spec/ruby/library/stringscanner/search_full_spec.rb
@@ -27,4 +27,10 @@ describe "StringScanner#search_full" do
     @s.search_full(/This/, true, true).should == "This"
     @s.pos.should == 4
   end
+
+  it "raises TypeError if given a String" do
+    -> {
+      @s.search_full('T', true, true)
+    }.should raise_error(TypeError, 'wrong argument type String (expected Regexp)')
+  end
 end
diff --git a/spec/ruby/library/stringscanner/shared/matched_size.rb b/spec/ruby/library/stringscanner/shared/matched_size.rb
deleted file mode 100644
index 92174733f7..0000000000
--- a/spec/ruby/library/stringscanner/shared/matched_size.rb
+++ /dev/null
@@ -1,21 +0,0 @@
-describe :strscan_matched_size, shared: true do
-  before :each do
-    @s = StringScanner.new("This is a test")
-  end
-
-  it "returns the size of the most recent match" do
-    @s.check(/This/)
-    @s.send(@method).should == 4
-    @s.send(@method).should == 4
-    @s.scan(//)
-    @s.send(@method).should == 0
-  end
-
-  it "returns nil if there was no recent match" do
-    @s.send(@method).should == nil
-    @s.check(/\d+/)
-    @s.send(@method).should == nil
-    @s.terminate
-    @s.send(@method).should == nil
-  end
-end
diff --git a/spec/ruby/library/stringscanner/size_spec.rb b/spec/ruby/library/stringscanner/size_spec.rb
new file mode 100644
index 0000000000..3e475489e3
--- /dev/null
+++ b/spec/ruby/library/stringscanner/size_spec.rb
@@ -0,0 +1,17 @@
+require_relative '../../spec_helper'
+require 'strscan'
+
+describe "StringScanner#size" do
+  before :each do
+    @s = StringScanner.new("This is a test")
+  end
+
+  it "returns the number of captures groups of the last match" do
+    @s.scan(/(.)(.)(.)/)
+    @s.size.should == 4
+  end
+
+  it "returns nil if there is no last match" do
+    @s.size.should == nil
+  end
+end
diff --git a/spec/ruby/library/stringscanner/skip_until_spec.rb b/spec/ruby/library/stringscanner/skip_until_spec.rb
index 73eb91b8ad..7b56f13e4f 100644
--- a/spec/ruby/library/stringscanner/skip_until_spec.rb
+++ b/spec/ruby/library/stringscanner/skip_until_spec.rb
@@ -15,4 +15,10 @@ describe "StringScanner#skip_until" do
   it "returns nil if no match was found" do
     @s.skip_until(/d+/).should == nil
   end
+
+  it "raises TypeError if given a String" do
+    -> {
+      @s.skip_until('T')
+    }.should raise_error(TypeError, 'wrong argument type String (expected Regexp)')
+  end
 end
diff --git a/spec/ruby/optional/capi/class_spec.rb b/spec/ruby/optional/capi/class_spec.rb
index c2424668b9..a2d8b3e38a 100644
--- a/spec/ruby/optional/capi/class_spec.rb
+++ b/spec/ruby/optional/capi/class_spec.rb
@@ -12,6 +12,7 @@ autoload :ClassIdUnderAutoload, "#{object_path}/class_id_under_autoload_spec"
 describe :rb_path_to_class, shared: true do
   it "returns a class or module from a scoped String" do
     @s.send(@method, "CApiClassSpecs::A::B").should equal(CApiClassSpecs::A::B)
+    @s.send(@method, "CApiClassSpecs::A::M").should equal(CApiClassSpecs::A::M)
   end
 
   it "resolves autoload constants" do
@@ -27,7 +28,9 @@ describe :rb_path_to_class, shared: true do
   end
 
   it "raises a TypeError if the constant is not a class or module" do
-    -> { @s.send(@method, "CApiClassSpecs::A::C") }.should raise_error(TypeError)
+    -> {
+      @s.send(@method, "CApiClassSpecs::A::C")
+    }.should raise_error(TypeError, 'CApiClassSpecs::A::C does not refer to class/module')
   end
 
   it "raises an ArgumentError even if a constant in the path exists on toplevel" do
diff --git a/spec/ruby/optional/capi/ext/string_spec.c b/spec/ruby/optional/capi/ext/string_spec.c
index 099363c951..2a21304a10 100644
--- a/spec/ruby/optional/capi/ext/string_spec.c
+++ b/spec/ruby/optional/capi/ext/string_spec.c
@@ -577,6 +577,14 @@ static VALUE string_spec_rb_str_catf(VALUE self, VALUE mesg) {
   return rb_str_catf(mesg, "fmt %d %d number", 41, 6);
 }
 
+static VALUE string_spec_rb_str_locktmp(VALUE self, VALUE str) {
+  return rb_str_locktmp(str);
+}
+
+static VALUE string_spec_rb_str_unlocktmp(VALUE self, VALUE str) {
+  return rb_str_unlocktmp(str);
+}
+
 void Init_string_spec(void) {
   VALUE cls = rb_define_class("CApiStringSpecs", rb_cObject);
   rb_define_method(cls, "rb_cstr2inum", string_spec_rb_cstr2inum, 2);
@@ -672,6 +680,8 @@ void Init_string_spec(void) {
   rb_define_method(cls, "rb_utf8_str_new_cstr", string_spec_rb_utf8_str_new_cstr, 0);
   rb_define_method(cls, "rb_str_vcatf", string_spec_rb_str_vcatf, 1);
   rb_define_method(cls, "rb_str_catf", string_spec_rb_str_catf, 1);
+  rb_define_method(cls, "rb_str_locktmp", string_spec_rb_str_locktmp, 1);
+  rb_define_method(cls, "rb_str_unlocktmp", string_spec_rb_str_unlocktmp, 1);
 }
 
 #ifdef __cplusplus
diff --git a/spec/ruby/optional/capi/fixtures/class.rb b/spec/ruby/optional/capi/fixtures/class.rb
index dbb0b69967..193c7174e0 100644
--- a/spec/ruby/optional/capi/fixtures/class.rb
+++ b/spec/ruby/optional/capi/fixtures/class.rb
@@ -87,5 +87,8 @@ class CApiClassSpecs
 
     class B
     end
+
+    module M
+    end
   end
 end
diff --git a/spec/ruby/optional/capi/string_spec.rb b/spec/ruby/optional/capi/string_spec.rb
index 3cd88a7390..ce387ffa49 100644
--- a/spec/ruby/optional/capi/string_spec.rb
+++ b/spec/ruby/optional/capi/string_spec.rb
@@ -1209,4 +1209,31 @@ end
       str.should == "test fmt 41 6 number"
     end
   end
+
+  describe "rb_str_locktmp" do
+    it "raises an error when trying to lock an already locked string" do
+      str = "test"
+      @s.rb_str_locktmp(str).should == str
+      -> { @s.rb_str_locktmp(str) }.should raise_error(RuntimeError, 'temporal locking already locked string')
+    end
+
+    it "locks a string so that modifications would raise an error" do
+      str = "test"
+      @s.rb_str_locktmp(str).should == str
+      -> { str.upcase! }.should raise_error(RuntimeError, 'can\'t modify string; temporarily locked')
+    end
+  end
+
+  describe "rb_str_unlocktmp" do
+    it "unlocks a locked string" do
+      str = "test"
+      @s.rb_str_locktmp(str)
+      @s.rb_str_unlocktmp(str).should == str
+      str.upcase!.should == "TEST"
+    end
+
+    it "raises an error when trying to unlock an already unlocked string" do
+      -> { @s.rb_str_unlocktmp("test") }.should raise_error(RuntimeError, 'temporal unlocking already unlocked string')
+    end
+  end
 end