From 6204e0804b24f1675b49d5880da014411bcfb831 Mon Sep 17 00:00:00 2001
From: eregon <eregon@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Sun, 20 Jan 2019 20:38:57 +0000
Subject: Update to ruby/spec@35a9fba

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66888 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 spec/ruby/core/array/difference_spec.rb            |   2 +-
 spec/ruby/core/array/to_h_spec.rb                  |  39 +++++++-
 spec/ruby/core/binding/fixtures/location.rb        |   6 ++
 spec/ruby/core/binding/source_location_spec.rb     |  11 +++
 spec/ruby/core/dir/children_spec.rb                |  66 +++++++++++++
 spec/ruby/core/dir/each_child_spec.rb              |  52 ++++++++++
 spec/ruby/core/enumerable/chain_spec.rb            |  22 +++++
 spec/ruby/core/enumerable/to_h_spec.rb             |  44 ++++++++-
 .../enumerator/arithmetic_sequence/begin_spec.rb   |  11 +++
 .../enumerator/arithmetic_sequence/each_spec.rb    |  19 ++++
 .../enumerator/arithmetic_sequence/end_spec.rb     |  11 +++
 .../core/enumerator/arithmetic_sequence/eq_spec.rb |  20 ++++
 .../arithmetic_sequence/exclude_end_spec.rb        |  19 ++++
 .../enumerator/arithmetic_sequence/first_spec.rb   |  11 +++
 .../enumerator/arithmetic_sequence/hash_spec.rb    |  22 +++++
 .../enumerator/arithmetic_sequence/inspect_spec.rb |  22 +++++
 .../enumerator/arithmetic_sequence/last_spec.rb    |  11 +++
 .../enumerator/arithmetic_sequence/new_spec.rb     |  19 ++++
 .../enumerator/arithmetic_sequence/size_spec.rb    |  19 ++++
 .../enumerator/arithmetic_sequence/step_spec.rb    |  15 +++
 spec/ruby/core/enumerator/chain/each_spec.rb       |  17 ++++
 spec/ruby/core/enumerator/chain/initialize_spec.rb |  33 +++++++
 spec/ruby/core/enumerator/chain/inspect_spec.rb    |  16 ++++
 spec/ruby/core/enumerator/chain/rewind_spec.rb     |  53 +++++++++++
 spec/ruby/core/enumerator/chain/size_spec.rb       |  24 +++++
 spec/ruby/core/enumerator/each_spec.rb             |  88 ++++++++++++++++-
 spec/ruby/core/enumerator/inject_spec.rb           |  15 ---
 spec/ruby/core/enumerator/lazy/filter_spec.rb      |   8 ++
 spec/ruby/core/enumerator/new_spec.rb              |  39 +++++++-
 spec/ruby/core/enumerator/next_spec.rb             |  25 ++++-
 spec/ruby/core/enumerator/plus_spec.rb             |  35 +++++++
 spec/ruby/core/enumerator/rewind_spec.rb           |  36 ++++++-
 spec/ruby/core/env/filter_spec.rb                  |  15 +++
 spec/ruby/core/env/select_spec.rb                  |  32 +------
 spec/ruby/core/env/shared/select.rb                |  32 +++++++
 spec/ruby/core/env/to_h_spec.rb                    |  54 +++++++++--
 spec/ruby/core/exception/full_message_spec.rb      |  37 ++++++++
 spec/ruby/core/exception/key_error_spec.rb         |  15 +++
 spec/ruby/core/exception/name_error_spec.rb        |  11 +++
 spec/ruby/core/exception/no_method_error_spec.rb   |  13 ++-
 spec/ruby/core/file/open_spec.rb                   |  27 ++++++
 spec/ruby/core/hash/merge_spec.rb                  |  11 +++
 spec/ruby/core/hash/shared/update.rb               |  12 +++
 spec/ruby/core/hash/to_h_spec.rb                   |  46 +++++++--
 spec/ruby/core/io/ungetbyte_spec.rb                |   9 +-
 spec/ruby/core/kernel/Complex_spec.rb              |  48 ++++++++++
 spec/ruby/core/kernel/Float_spec.rb                |  25 +++++
 spec/ruby/core/kernel/Integer_spec.rb              | 105 +++++++++++++++++++++
 spec/ruby/core/kernel/match_spec.rb                |   8 ++
 spec/ruby/core/kernel/shared/load.rb               |   3 +-
 spec/ruby/core/kernel/shared/require.rb            |   3 +-
 spec/ruby/core/method/compose_spec.rb              | 101 ++++++++++++++++++++
 spec/ruby/core/method/fixtures/classes.rb          |  25 +++++
 spec/ruby/core/module/attr_spec.rb                 |   3 +-
 spec/ruby/core/module/autoload_spec.rb             |   3 +-
 spec/ruby/core/module/method_defined_spec.rb       |  51 ++++++++++
 .../core/module/private_method_defined_spec.rb     |  50 ++++++++++
 .../core/module/protected_method_defined_spec.rb   |  50 ++++++++++
 spec/ruby/core/module/refine_spec.rb               |  57 +++++++++++
 spec/ruby/core/nil/match_spec.rb                   |  19 ++++
 spec/ruby/core/numeric/step_spec.rb                |  14 +++
 spec/ruby/core/proc/compose_spec.rb                |  94 ++++++++++++++++++
 spec/ruby/core/proc/shared/compose.rb              |  47 +++++++++
 spec/ruby/core/process/fixtures/in.txt             |   1 +
 spec/ruby/core/process/spawn_spec.rb               |  34 ++++++-
 spec/ruby/core/range/case_compare_spec.rb          |  12 ++-
 spec/ruby/core/range/fixtures/classes.rb           |  22 +++++
 spec/ruby/core/range/new_spec.rb                   |  26 +++++
 spec/ruby/core/range/percent_spec.rb               |  18 ++++
 spec/ruby/core/range/shared/cover.rb               |  60 ++++++++++++
 spec/ruby/core/range/step_spec.rb                  |  35 ++++---
 spec/ruby/core/string/split_spec.rb                |  12 +++
 spec/ruby/core/struct/to_h_spec.rb                 |  43 ++++++++-
 spec/ruby/core/tracepoint/eval_script_spec.rb      |  22 +++++
 .../core/tracepoint/instruction_sequence_spec.rb   |  23 +++++
 75 files changed, 2049 insertions(+), 109 deletions(-)
 create mode 100644 spec/ruby/core/binding/fixtures/location.rb
 create mode 100644 spec/ruby/core/binding/source_location_spec.rb
 create mode 100644 spec/ruby/core/enumerable/chain_spec.rb
 create mode 100644 spec/ruby/core/enumerator/arithmetic_sequence/begin_spec.rb
 create mode 100644 spec/ruby/core/enumerator/arithmetic_sequence/each_spec.rb
 create mode 100644 spec/ruby/core/enumerator/arithmetic_sequence/end_spec.rb
 create mode 100644 spec/ruby/core/enumerator/arithmetic_sequence/eq_spec.rb
 create mode 100644 spec/ruby/core/enumerator/arithmetic_sequence/exclude_end_spec.rb
 create mode 100644 spec/ruby/core/enumerator/arithmetic_sequence/first_spec.rb
 create mode 100644 spec/ruby/core/enumerator/arithmetic_sequence/hash_spec.rb
 create mode 100644 spec/ruby/core/enumerator/arithmetic_sequence/inspect_spec.rb
 create mode 100644 spec/ruby/core/enumerator/arithmetic_sequence/last_spec.rb
 create mode 100644 spec/ruby/core/enumerator/arithmetic_sequence/new_spec.rb
 create mode 100644 spec/ruby/core/enumerator/arithmetic_sequence/size_spec.rb
 create mode 100644 spec/ruby/core/enumerator/arithmetic_sequence/step_spec.rb
 create mode 100644 spec/ruby/core/enumerator/chain/each_spec.rb
 create mode 100644 spec/ruby/core/enumerator/chain/initialize_spec.rb
 create mode 100644 spec/ruby/core/enumerator/chain/inspect_spec.rb
 create mode 100644 spec/ruby/core/enumerator/chain/rewind_spec.rb
 create mode 100644 spec/ruby/core/enumerator/chain/size_spec.rb
 delete mode 100644 spec/ruby/core/enumerator/inject_spec.rb
 create mode 100644 spec/ruby/core/enumerator/lazy/filter_spec.rb
 create mode 100644 spec/ruby/core/enumerator/plus_spec.rb
 create mode 100644 spec/ruby/core/env/filter_spec.rb
 create mode 100644 spec/ruby/core/env/shared/select.rb
 create mode 100644 spec/ruby/core/exception/key_error_spec.rb
 create mode 100644 spec/ruby/core/method/compose_spec.rb
 create mode 100644 spec/ruby/core/nil/match_spec.rb
 create mode 100644 spec/ruby/core/proc/compose_spec.rb
 create mode 100644 spec/ruby/core/proc/shared/compose.rb
 create mode 100644 spec/ruby/core/process/fixtures/in.txt
 create mode 100644 spec/ruby/core/range/percent_spec.rb
 create mode 100644 spec/ruby/core/tracepoint/eval_script_spec.rb
 create mode 100644 spec/ruby/core/tracepoint/instruction_sequence_spec.rb

(limited to 'spec/ruby/core')

diff --git a/spec/ruby/core/array/difference_spec.rb b/spec/ruby/core/array/difference_spec.rb
index 33ea8e1f3c..a357657967 100644
--- a/spec/ruby/core/array/difference_spec.rb
+++ b/spec/ruby/core/array/difference_spec.rb
@@ -4,7 +4,7 @@ require_relative 'shared/difference'
 
 ruby_version_is "2.6" do
   describe "Array#difference" do
-    it_behaves_like :array_binary_difference, :-
+    it_behaves_like :array_binary_difference, :difference
 
     it "returns a copy when called without any parameter" do
       x = [1, 2, 3, 2]
diff --git a/spec/ruby/core/array/to_h_spec.rb b/spec/ruby/core/array/to_h_spec.rb
index e845d2c950..27a0b6112f 100644
--- a/spec/ruby/core/array/to_h_spec.rb
+++ b/spec/ruby/core/array/to_h_spec.rb
@@ -36,9 +36,42 @@ describe "Array#to_h" do
   end
 
   ruby_version_is "2.6" do
-    it "converts [key, value] pairs returned by the block to a hash" do
-      i = 0
-      [:a, :b].to_h {|k| [k, i += 1]}.should == { a: 1, b: 2 }
+    context "with block" do
+      it "converts [key, value] pairs returned by the block to a Hash" do
+        [:a, :b].to_h { |k| [k, k.to_s] }.should == { a: 'a', b: 'b' }
+      end
+
+      it "raises ArgumentError if block returns longer or shorter array" do
+        -> do
+          [:a, :b].to_h { |k| [k, k.to_s, 1] }
+        end.should raise_error(ArgumentError, /wrong array length at 0/)
+
+        -> do
+          [:a, :b].to_h { |k| [k] }
+        end.should raise_error(ArgumentError, /wrong array length at 0/)
+      end
+
+      it "raises TypeError if block returns something other than Array" do
+        -> do
+          [:a, :b].to_h { |k| "not-array" }
+        end.should raise_error(TypeError, /wrong element type String at 0/)
+      end
+
+      it "coerces returned pair to Array with #to_ary" do
+        x = mock('x')
+        x.stub!(:to_ary).and_return([:b, 'b'])
+
+        [:a].to_h { |k| x }.should == { :b => 'b' }
+      end
+
+      it "does not coerce returned pair to Array with #to_a" do
+        x = mock('x')
+        x.stub!(:to_a).and_return([:b, 'b'])
+
+        -> do
+          [:a].to_h { |k| x }
+        end.should raise_error(TypeError, /wrong element type MockObject at 0/)
+      end
     end
   end
 end
diff --git a/spec/ruby/core/binding/fixtures/location.rb b/spec/ruby/core/binding/fixtures/location.rb
new file mode 100644
index 0000000000..a78ae75731
--- /dev/null
+++ b/spec/ruby/core/binding/fixtures/location.rb
@@ -0,0 +1,6 @@
+module BindingSpecs
+  module LocationMethod
+    FILE_PATH = __FILE__
+    TEST_BINDING = binding
+  end
+end
diff --git a/spec/ruby/core/binding/source_location_spec.rb b/spec/ruby/core/binding/source_location_spec.rb
new file mode 100644
index 0000000000..e562bc65c8
--- /dev/null
+++ b/spec/ruby/core/binding/source_location_spec.rb
@@ -0,0 +1,11 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/location'
+
+ruby_version_is "2.6" do
+  describe "Binding#source_location" do
+    it "returns an [file, line] pair" do
+      b = BindingSpecs::LocationMethod::TEST_BINDING
+      b.source_location.should == [BindingSpecs::LocationMethod::FILE_PATH, 4]
+    end
+  end
+end
diff --git a/spec/ruby/core/dir/children_spec.rb b/spec/ruby/core/dir/children_spec.rb
index 4bc64934b3..c6329b416f 100644
--- a/spec/ruby/core/dir/children_spec.rb
+++ b/spec/ruby/core/dir/children_spec.rb
@@ -70,3 +70,69 @@ ruby_version_is "2.5" do
     end
   end
 end
+
+ruby_version_is "2.6" do
+  describe "Dir#children" do
+    before :all do
+      DirSpecs.create_mock_dirs
+    end
+
+    before :each do
+      @internal = Encoding.default_internal
+    end
+
+    after :all do
+      DirSpecs.delete_mock_dirs
+    end
+
+    after :each do
+      Encoding.default_internal = @internal
+      @dir.close if @dir
+    end
+
+    it "returns an Array of filenames in an existing directory including dotfiles" do
+      @dir = Dir.new(DirSpecs.mock_dir)
+      a = @dir.children.sort
+      @dir.close
+
+      a.should == DirSpecs.expected_paths - %w[. ..]
+
+      @dir = Dir.new("#{DirSpecs.mock_dir}/deeply/nested")
+      a = @dir.children.sort
+      a.should == %w|.dotfile.ext directory|
+    end
+
+    it "accepts an options Hash" do
+      @dir = Dir.new("#{DirSpecs.mock_dir}/deeply/nested", encoding: "utf-8")
+      a = @dir.children.sort
+      a.should == %w|.dotfile.ext directory|
+    end
+
+    it "returns children encoded with the filesystem encoding by default" do
+      # This spec depends on the locale not being US-ASCII because if it is, the
+      # children that are not ascii_only? will be ASCII-8BIT encoded.
+      @dir = Dir.new(File.join(DirSpecs.mock_dir, 'special'))
+      children = @dir.children.sort
+      encoding = Encoding.find("filesystem")
+      encoding = Encoding::ASCII_8BIT if encoding == Encoding::US_ASCII
+      platform_is_not :windows do
+        children.should include("こんにちは.txt".force_encoding(encoding))
+      end
+      children.first.encoding.should equal(Encoding.find("filesystem"))
+    end
+
+    it "returns children encoded with the specified encoding" do
+      path = File.join(DirSpecs.mock_dir, 'special')
+      @dir = Dir.new(path, encoding: "euc-jp")
+      children = @dir.children.sort
+      children.first.encoding.should equal(Encoding::EUC_JP)
+    end
+
+    it "returns children transcoded to the default internal encoding" do
+      Encoding.default_internal = Encoding::EUC_KR
+      @dir = Dir.new(File.join(DirSpecs.mock_dir, 'special'))
+      children = @dir.children.sort
+      children.first.encoding.should equal(Encoding::EUC_KR)
+    end
+  end
+end
diff --git a/spec/ruby/core/dir/each_child_spec.rb b/spec/ruby/core/dir/each_child_spec.rb
index 913b9cb96f..c04d212bfa 100644
--- a/spec/ruby/core/dir/each_child_spec.rb
+++ b/spec/ruby/core/dir/each_child_spec.rb
@@ -51,3 +51,55 @@ ruby_version_is "2.5" do
     end
   end
 end
+
+ruby_version_is "2.6" do
+  describe "Dir#each_child" do
+    before :all do
+      DirSpecs.create_mock_dirs
+    end
+
+    after :all do
+      DirSpecs.delete_mock_dirs
+    end
+
+    after :each do
+      @dir.close if @dir
+    end
+
+    it "yields all names in an existing directory to the provided block" do
+      a, b = [], []
+      @dir = Dir.new(DirSpecs.mock_dir)
+      @dir2 = Dir.new("#{DirSpecs.mock_dir}/deeply/nested")
+
+      @dir.each_child { |f| a << f }
+      @dir2.each_child { |f| b << f }
+      @dir2.close
+
+      a.sort.should == DirSpecs.expected_paths - %w|. ..|
+      b.sort.should == %w|.dotfile.ext directory|
+    end
+
+    it "returns self when successful" do
+      @dir = Dir.new(DirSpecs.mock_dir)
+      @dir.each_child { |f| f }.should == @dir
+    end
+
+    describe "when no block is given" do
+      it "returns an Enumerator" do
+        @dir = Dir.new(DirSpecs.mock_dir)
+
+        @dir.each_child.should be_an_instance_of(Enumerator)
+        @dir.each_child.to_a.sort.should == DirSpecs.expected_paths - %w|. ..|
+      end
+
+      describe "returned Enumerator" do
+        describe "size" do
+          it "should return nil" do
+            @dir = Dir.new(DirSpecs.mock_dir)
+            @dir.each_child.size.should == nil
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerable/chain_spec.rb b/spec/ruby/core/enumerable/chain_spec.rb
new file mode 100644
index 0000000000..0e86a02905
--- /dev/null
+++ b/spec/ruby/core/enumerable/chain_spec.rb
@@ -0,0 +1,22 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+ruby_version_is "2.6" do
+  describe "Enumerable#chain" do
+    before :each do
+      ScratchPad.record []
+    end
+
+    it "returns a chain of self and provided enumerables" do
+      one = EnumerableSpecs::Numerous.new(1)
+      two = EnumerableSpecs::Numerous.new(2)
+      three = EnumerableSpecs::Numerous.new(3)
+
+      chain = one.chain(two, three)
+
+      chain.should be_an_instance_of(Enumerator::Chain)
+      chain.each { |item| ScratchPad << item }
+      ScratchPad.recorded.should == [1, 2, 3]
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerable/to_h_spec.rb b/spec/ruby/core/enumerable/to_h_spec.rb
index 966325c736..f15ced122e 100644
--- a/spec/ruby/core/enumerable/to_h_spec.rb
+++ b/spec/ruby/core/enumerable/to_h_spec.rb
@@ -45,10 +45,46 @@ describe "Enumerable#to_h" do
   end
 
   ruby_version_is "2.6" do
-    it "converts [key, value] pairs returned by the block to a hash" do
-      enum = EnumerableSpecs::EachDefiner.new(:a, :b)
-      i = 0
-      enum.to_h {|k| [k, i += 1]}.should == { a: 1, b: 2 }
+    context "with block" do
+      before do
+        @enum = EnumerableSpecs::EachDefiner.new(:a, :b)
+      end
+
+      it "converts [key, value] pairs returned by the block to a hash" do
+        @enum.to_h { |k| [k, k.to_s] }.should == { a: 'a', b: 'b' }
+      end
+
+      it "raises ArgumentError if block returns longer or shorter array" do
+        -> do
+          @enum.to_h { |k| [k, k.to_s, 1] }
+        end.should raise_error(ArgumentError, /element has wrong array length/)
+
+        -> do
+          @enum.to_h { |k| [k] }
+        end.should raise_error(ArgumentError, /element has wrong array length/)
+      end
+
+      it "raises TypeError if block returns something other than Array" do
+        -> do
+          @enum.to_h { |k| "not-array" }
+        end.should raise_error(TypeError, /wrong element type String/)
+      end
+
+      it "coerces returned pair to Array with #to_ary" do
+        x = mock('x')
+        x.stub!(:to_ary).and_return([:b, 'b'])
+
+        @enum.to_h { |k| x }.should == { :b => 'b' }
+      end
+
+      it "does not coerce returned pair to Array with #to_a" do
+        x = mock('x')
+        x.stub!(:to_a).and_return([:b, 'b'])
+
+        -> do
+          @enum.to_h { |k| x }
+        end.should raise_error(TypeError, /wrong element type MockObject/)
+      end
     end
   end
 end
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/begin_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/begin_spec.rb
new file mode 100644
index 0000000000..c8d91ebaec
--- /dev/null
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/begin_spec.rb
@@ -0,0 +1,11 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::ArithmeticSequence#begin" do
+    it "returns the begin of the sequence" do
+      1.step(10).begin.should == 1
+      (1..10).step.begin.should == 1
+      (1...10).step.begin.should == 1
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/each_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/each_spec.rb
new file mode 100644
index 0000000000..d7edf3a21f
--- /dev/null
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/each_spec.rb
@@ -0,0 +1,19 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::ArithmeticSequence#each" do
+    before :each do
+      ScratchPad.record []
+      @seq = 1.step(10, 4)
+    end
+
+    it "calls given block on each item of the sequence" do
+      @seq.each { |item| ScratchPad << item }
+      ScratchPad.recorded.should == [1, 5, 9]
+    end
+
+    it "returns self" do
+      @seq.each { |item| }.should equal(@seq)
+    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
new file mode 100644
index 0000000000..5a436e8167
--- /dev/null
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/end_spec.rb
@@ -0,0 +1,11 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::ArithmeticSequence#end" do
+    it "returns the end of the sequence" do
+      1.step(10).end.should == 10
+      (1..10).step.end.should == 10
+      (1...10).step(17).end.should == 10
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/eq_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/eq_spec.rb
new file mode 100644
index 0000000000..7895f98047
--- /dev/null
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/eq_spec.rb
@@ -0,0 +1,20 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::ArithmeticSequence#==" do
+    it "returns true if begin, end, step and exclude_end? are equal" do
+      1.step(10).should == 1.step(10)
+      1.step(10, 5).should == 1.step(10, 5)
+
+      (1..10).step.should == (1..10).step
+      (1...10).step(8).should == (1...10).step(8)
+
+      # both have exclude_end? == false
+      (1..10).step(100).should == 1.step(10, 100)
+
+      ((1..10).step == (1..11).step).should == false
+      ((1..10).step == (1...10).step).should == false
+      ((1..10).step == (1..10).step(2)).should == false
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/exclude_end_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/exclude_end_spec.rb
new file mode 100644
index 0000000000..8ce0ce0cd9
--- /dev/null
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/exclude_end_spec.rb
@@ -0,0 +1,19 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::ArithmeticSequence#exclude_end?" do
+    context "when created using Numeric#step" do
+      it "always returns false" do
+        1.step(10).exclude_end?.should == false
+        10.step(1).exclude_end?.should == false
+      end
+    end
+
+    context "when created using Range#step" do
+      it "mirrors range.exclude_end?" do
+        (1...10).step.exclude_end?.should == true
+        (1..10).step.exclude_end?.should == false
+      end
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/first_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/first_spec.rb
new file mode 100644
index 0000000000..43c520d1f0
--- /dev/null
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/first_spec.rb
@@ -0,0 +1,11 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::ArithmeticSequence#first" do
+    it "returns the first element of the sequence" do
+      1.step(10).first.should == 1
+      (1..10).step.first.should == 1
+      (1...10).step.first.should == 1
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/hash_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/hash_spec.rb
new file mode 100644
index 0000000000..236f845f41
--- /dev/null
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/hash_spec.rb
@@ -0,0 +1,22 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::ArithmeticSequence#hash" do
+    it "is based on begin, end, step and exclude_end?" do
+      1.step(10).hash.should be_an_instance_of(Integer)
+
+      1.step(10).hash.should == 1.step(10).hash
+      1.step(10, 5).hash.should == 1.step(10, 5).hash
+
+      (1..10).step.hash.should == (1..10).step.hash
+      (1...10).step(8).hash.should == (1...10).step(8).hash
+
+      # both have exclude_end? == false
+      (1..10).step(100).hash.should == 1.step(10, 100).hash
+
+      ((1..10).step.hash == (1..11).step.hash).should == false
+      ((1..10).step.hash == (1...10).step.hash).should == false
+      ((1..10).step.hash == (1..10).step(2).hash).should == false
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/inspect_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/inspect_spec.rb
new file mode 100644
index 0000000000..21e64a6b58
--- /dev/null
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/inspect_spec.rb
@@ -0,0 +1,22 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::ArithmeticSequence#inspect" do
+    context 'when Numeric#step is used' do
+      it "returns '(begin.step(end{, step}))'" do
+        1.step(10).inspect.should == "(1.step(10))"
+        1.step(10, 3).inspect.should == "(1.step(10, 3))"
+      end
+    end
+
+    context 'when Range#step is used' do
+      it "returns '((range).step{(step)})'" do
+        (1..10).step.inspect.should == "((1..10).step)"
+        (1..10).step(3).inspect.should == "((1..10).step(3))"
+
+        (1...10).step.inspect.should == "((1...10).step)"
+        (1...10).step(3).inspect.should == "((1...10).step(3))"
+      end
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/last_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/last_spec.rb
new file mode 100644
index 0000000000..ebb20090fc
--- /dev/null
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/last_spec.rb
@@ -0,0 +1,11 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::ArithmeticSequence#last" do
+    it "returns the last element of the sequence" do
+      1.step(10).last.should == 10
+      (1..10).step.last.should == 10
+      (1...10).step(4).last.should == 9
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/new_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/new_spec.rb
new file mode 100644
index 0000000000..5a62d3f346
--- /dev/null
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/new_spec.rb
@@ -0,0 +1,19 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::ArithmeticSequence.new" do
+    it "is not defined" do
+      lambda {
+        Enumerator::ArithmeticSequence.new
+      }.should raise_error(NoMethodError)
+    end
+  end
+
+  describe "Enumerator::ArithmeticSequence.allocate" do
+    it "is not defined" do
+      lambda {
+        Enumerator::ArithmeticSequence.allocate
+      }.should raise_error(TypeError, 'allocator undefined for Enumerator::ArithmeticSequence')
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/size_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/size_spec.rb
new file mode 100644
index 0000000000..00403b0238
--- /dev/null
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/size_spec.rb
@@ -0,0 +1,19 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::ArithmeticSequence#size" do
+    context "for finite sequence" do
+      it "returns the number of elements in this arithmetic sequence" do
+        1.step(10).size.should == 10
+        (1...10).step.size.should == 9
+      end
+    end
+
+    context "for infinite sequence" do
+      it "returns Infinity" do
+        1.step(Float::INFINITY).size.should == Float::INFINITY
+        (1..Float::INFINITY).step.size.should == Float::INFINITY
+      end
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/arithmetic_sequence/step_spec.rb b/spec/ruby/core/enumerator/arithmetic_sequence/step_spec.rb
new file mode 100644
index 0000000000..20a5cb6e7b
--- /dev/null
+++ b/spec/ruby/core/enumerator/arithmetic_sequence/step_spec.rb
@@ -0,0 +1,15 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::ArithmeticSequence#step" do
+    it "returns the original value given to step method" do
+      (1..10).step.step.should == 1
+      (1..10).step(3).step.should == 3
+      (1..10).step(0).step.should == 0
+
+      1.step(10).step.should == 1
+      1.step(10, 3).step.should == 3
+      1.step(10, 0).step.should == 0
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/chain/each_spec.rb b/spec/ruby/core/enumerator/chain/each_spec.rb
new file mode 100644
index 0000000000..dab2c1cf1d
--- /dev/null
+++ b/spec/ruby/core/enumerator/chain/each_spec.rb
@@ -0,0 +1,17 @@
+require_relative '../../../spec_helper'
+require_relative '../../enumerable/fixtures/classes'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::Chain#each" do
+    it "calls each on its consistuents as needed" do
+      a = EnumerableSpecs::EachCounter.new(:a, :b)
+      b = EnumerableSpecs::EachCounter.new(:c, :d)
+
+      ScratchPad.record []
+      Enumerator::Chain.new(a, b).each do |elem|
+        ScratchPad << elem << b.times_yielded
+      end
+      ScratchPad.recorded.should == [:a, 0, :b, 0, :c, 1, :d, 2]
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/chain/initialize_spec.rb b/spec/ruby/core/enumerator/chain/initialize_spec.rb
new file mode 100644
index 0000000000..4ede1b8670
--- /dev/null
+++ b/spec/ruby/core/enumerator/chain/initialize_spec.rb
@@ -0,0 +1,33 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::Chain#initialize" do
+    before :each do
+      @uninitialized = Enumerator::Chain.allocate
+    end
+
+    it "is a private method" do
+      Enumerator::Chain.should have_private_instance_method(:initialize, false)
+    end
+
+    it "returns self" do
+      @uninitialized.send(:initialize).should equal(@uninitialized)
+    end
+
+    it "accepts many arguments" do
+      @uninitialized.send(:initialize, 0..1, 2..3, 4..5).should equal(@uninitialized)
+    end
+
+    it "accepts arguments that are not Enumerable nor responding to :each" do
+      @uninitialized.send(:initialize, Object.new).should equal(@uninitialized)
+    end
+
+    describe "on frozen instance" do
+      it "raises a RuntimeError" do
+        lambda {
+          @uninitialized.freeze.send(:initialize)
+        }.should raise_error(RuntimeError)
+      end
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/chain/inspect_spec.rb b/spec/ruby/core/enumerator/chain/inspect_spec.rb
new file mode 100644
index 0000000000..a644d88c6f
--- /dev/null
+++ b/spec/ruby/core/enumerator/chain/inspect_spec.rb
@@ -0,0 +1,16 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::Chain#inspect" do
+    it "shows a representation of the Enumerator" do
+      Enumerator::Chain.new.inspect.should == "#<Enumerator::Chain: []>"
+      Enumerator::Chain.new(1..2, 3..4).inspect.should == "#<Enumerator::Chain: [1..2, 3..4]>"
+    end
+
+    it "calls inspect on its chain elements" do
+      obj = mock('inspect')
+      obj.should_receive(:inspect).and_return('some desc')
+      Enumerator::Chain.new(obj).inspect.should == "#<Enumerator::Chain: [some desc]>"
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/chain/rewind_spec.rb b/spec/ruby/core/enumerator/chain/rewind_spec.rb
new file mode 100644
index 0000000000..61b07b8c0a
--- /dev/null
+++ b/spec/ruby/core/enumerator/chain/rewind_spec.rb
@@ -0,0 +1,53 @@
+require_relative '../../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::Chain#rewind" do
+    before(:each) do
+      @obj = mock('obj')
+      @obj.should_receive(:each).any_number_of_times.and_yield(42)
+      @second = mock('obj')
+      @second.should_receive(:each).any_number_of_times.and_yield(:second)
+      @enum = Enumerator::Chain.new(@obj, @second)
+    end
+
+    it "returns self" do
+      @enum.rewind.should equal @enum
+    end
+
+    it "does nothing if receiver has not been iterated" do
+      @obj.should_not_receive(:rewind)
+      @obj.respond_to?(:rewind).should == true # sanity check
+      @enum.rewind
+    end
+
+    it "does nothing on objects that don't respond_to rewind" do
+      @obj.respond_to?(:rewind).should == false # sanity check
+      @enum.each {}
+      @enum.rewind
+    end
+
+    it "calls_rewind its objects" do
+      @obj.should_receive(:rewind)
+      @enum.each {}
+      @enum.rewind
+    end
+
+    it "calls_rewind in reverse order" do
+      @obj.should_not_receive(:rewind)
+      @second.should_receive(:rewind).and_raise(RuntimeError)
+      @enum.each {}
+      lambda { @enum.rewind }.should raise_error(RuntimeError)
+    end
+
+    it "calls rewind only for objects that have actually been iterated on" do
+      @obj = mock('obj')
+      @obj.should_receive(:each).any_number_of_times.and_raise(RuntimeError)
+      @enum = Enumerator::Chain.new(@obj, @second)
+
+      @obj.should_receive(:rewind)
+      @second.should_not_receive(:rewind)
+      lambda { @enum.each {} }.should raise_error(RuntimeError)
+      @enum.rewind
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/chain/size_spec.rb b/spec/ruby/core/enumerator/chain/size_spec.rb
new file mode 100644
index 0000000000..42c31ac10b
--- /dev/null
+++ b/spec/ruby/core/enumerator/chain/size_spec.rb
@@ -0,0 +1,24 @@
+require_relative '../../../spec_helper'
+require_relative '../../enumerable/fixtures/classes'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::Chain#size" do
+    it "returns the sum of the sizes of the elements" do
+      a = mock('size')
+      a.should_receive(:size).and_return(40)
+      Enumerator::Chain.new(a, [:a, :b]).size.should == 42
+    end
+
+    it "returns nil or Infinity for the first element of such a size" do
+      [nil, Float::INFINITY].each do |special|
+        a = mock('size')
+        a.should_receive(:size).and_return(40)
+        b = mock('special')
+        b.should_receive(:size).and_return(special)
+        c = mock('not called')
+        c.should_not_receive(:size)
+        Enumerator::Chain.new(a, b, c).size.should == special
+      end
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/each_spec.rb b/spec/ruby/core/enumerator/each_spec.rb
index e2a78a6a99..f66951851e 100644
--- a/spec/ruby/core/enumerator/each_spec.rb
+++ b/spec/ruby/core/enumerator/each_spec.rb
@@ -1,5 +1,89 @@
-require_relative '../../shared/enumerator/each'
+require_relative '../../spec_helper'
 
 describe "Enumerator#each" do
-  it_behaves_like :enum_each, :each
+  before :each do
+    object_each_with_arguments = Object.new
+    def object_each_with_arguments.each_with_arguments(arg, *args)
+      yield arg, *args
+      :method_returned
+    end
+
+    @enum_with_arguments = object_each_with_arguments.to_enum(:each_with_arguments, :arg0, :arg1, :arg2)
+
+    @enum_with_yielder = Enumerator.new {|y| y.yield :ok}
+  end
+
+  it "yields each element of self to the given block" do
+    acc = []
+    [1,2,3].to_enum.each {|e| acc << e }
+    acc.should == [1,2,3]
+  end
+
+  it "calls #each on the object given in the constructor by default" do
+    each = mock('each')
+    each.should_receive(:each)
+    each.to_enum.each {|e| e }
+  end
+
+  it "calls #each on the underlying object until it's exhausted" do
+    each = mock('each')
+    each.should_receive(:each).and_yield(1).and_yield(2).and_yield(3)
+    acc = []
+    each.to_enum.each {|e| acc << e }
+    acc.should == [1,2,3]
+  end
+
+  it "calls the method given in the constructor instead of #each" do
+    each = mock('peach')
+    each.should_receive(:peach)
+    each.to_enum(:peach).each {|e| e }
+  end
+
+  it "calls the method given in the constructor until it's exhausted" do
+    each = mock('each')
+    each.should_receive(:each).and_yield(1).and_yield(2).and_yield(3)
+    acc = []
+    each.to_enum.each {|e| acc << e }
+    acc.should == [1,2,3]
+  end
+
+  it "raises a NoMethodError if the object doesn't respond to #each" do
+    enum = Object.new.to_enum
+    lambda do
+      enum.each { |e| e }
+    end.should raise_error(NoMethodError)
+  end
+
+  it "returns self if not given arguments and not given a block" do
+    @enum_with_arguments.each.should equal(@enum_with_arguments)
+
+    @enum_with_yielder.each.should equal(@enum_with_yielder)
+  end
+
+  it "returns the same value from receiver.each if block is given" do
+    @enum_with_arguments.each {}.should equal(:method_returned)
+  end
+
+  it "passes given arguments at initialized to receiver.each" do
+    @enum_with_arguments.each.to_a.should == [[:arg0, :arg1, :arg2]]
+  end
+
+  it "requires multiple arguments" do
+    Enumerator.instance_method(:each).arity.should < 0
+  end
+
+  it "appends given arguments to receiver.each" do
+    @enum_with_arguments.each(:each0, :each1).to_a.should == [[:arg0, :arg1, :arg2, :each0, :each1]]
+    @enum_with_arguments.each(:each2, :each3).to_a.should == [[:arg0, :arg1, :arg2, :each2, :each3]]
+  end
+
+  it "returns the same value from receiver.each if block and arguments are given" do
+    @enum_with_arguments.each(:each1, :each2) {}.should equal(:method_returned)
+  end
+
+  it "returns new Enumerator if given arguments but not given a block" do
+    ret = @enum_with_arguments.each 1
+    ret.should be_an_instance_of(Enumerator)
+    ret.should_not equal(@enum_with_arguments)
+  end
 end
diff --git a/spec/ruby/core/enumerator/inject_spec.rb b/spec/ruby/core/enumerator/inject_spec.rb
deleted file mode 100644
index 326c7ed581..0000000000
--- a/spec/ruby/core/enumerator/inject_spec.rb
+++ /dev/null
@@ -1,15 +0,0 @@
-require_relative '../../shared/enumerator/each'
-
-describe "Enumerator#inject" do
-  it_behaves_like :enum_each, :each
-
-  it "works when chained against each_with_index" do
-    passed_values = []
-    [:a].each_with_index.inject(0) do |accumulator,value|
-      passed_values << value
-      accumulator + 1
-    end.should == 1
-    passed_values.should == [[:a,0]]
-  end
-
-end
diff --git a/spec/ruby/core/enumerator/lazy/filter_spec.rb b/spec/ruby/core/enumerator/lazy/filter_spec.rb
new file mode 100644
index 0000000000..2ababa69cc
--- /dev/null
+++ b/spec/ruby/core/enumerator/lazy/filter_spec.rb
@@ -0,0 +1,8 @@
+require_relative '../../../spec_helper'
+require_relative 'shared/select'
+
+ruby_version_is "2.6" do
+  describe "Enumerator::Lazy#filter" do
+    it_behaves_like :enumerator_lazy_select, :filter
+  end
+end
diff --git a/spec/ruby/core/enumerator/new_spec.rb b/spec/ruby/core/enumerator/new_spec.rb
index 86d2d38022..170809dbc1 100644
--- a/spec/ruby/core/enumerator/new_spec.rb
+++ b/spec/ruby/core/enumerator/new_spec.rb
@@ -1,6 +1,41 @@
 require_relative '../../spec_helper'
-require_relative '../../shared/enumerator/new'
 
 describe "Enumerator.new" do
-  it_behaves_like :enum_new, :new
+  it "creates a new custom enumerator with the given object, iterator and arguments" do
+    enum = Enumerator.new(1, :upto, 3)
+    enum.should be_an_instance_of(Enumerator)
+  end
+
+  it "creates a new custom enumerator that responds to #each" do
+    enum = Enumerator.new(1, :upto, 3)
+    enum.respond_to?(:each).should == true
+  end
+
+  it "creates a new custom enumerator that runs correctly" do
+    Enumerator.new(1, :upto, 3).map{|x|x}.should == [1,2,3]
+  end
+
+  it "aliases the second argument to :each" do
+    Enumerator.new(1..2).to_a.should == Enumerator.new(1..2, :each).to_a
+  end
+
+  it "doesn't check for the presence of the iterator method" do
+    Enumerator.new(nil).should be_an_instance_of(Enumerator)
+  end
+
+  it "uses the latest define iterator method" do
+    class StrangeEach
+      def each
+        yield :foo
+      end
+    end
+    enum = Enumerator.new(StrangeEach.new)
+    enum.to_a.should == [:foo]
+    class StrangeEach
+      def each
+        yield :bar
+      end
+    end
+    enum.to_a.should == [:bar]
+  end
 end
diff --git a/spec/ruby/core/enumerator/next_spec.rb b/spec/ruby/core/enumerator/next_spec.rb
index 1d3baf54d7..e0d3c0a39b 100644
--- a/spec/ruby/core/enumerator/next_spec.rb
+++ b/spec/ruby/core/enumerator/next_spec.rb
@@ -1,6 +1,27 @@
 require_relative '../../spec_helper'
-require_relative '../../shared/enumerator/next'
 
 describe "Enumerator#next" do
-  it_behaves_like :enum_next,:next
+  before :each do
+    @enum = 1.upto(3)
+  end
+
+  it "returns the next element of the enumeration" do
+    @enum.next.should == 1
+    @enum.next.should == 2
+    @enum.next.should == 3
+  end
+
+  it "raises a StopIteration exception at the end of the stream" do
+    3.times { @enum.next }
+    lambda { @enum.next }.should raise_error(StopIteration)
+  end
+
+  it "cannot be called again until the enumerator is rewound" do
+    3.times { @enum.next }
+    lambda { @enum.next }.should raise_error(StopIteration)
+    lambda { @enum.next }.should raise_error(StopIteration)
+    lambda { @enum.next }.should raise_error(StopIteration)
+    @enum.rewind
+    @enum.next.should == 1
+  end
 end
diff --git a/spec/ruby/core/enumerator/plus_spec.rb b/spec/ruby/core/enumerator/plus_spec.rb
new file mode 100644
index 0000000000..c9bae08b04
--- /dev/null
+++ b/spec/ruby/core/enumerator/plus_spec.rb
@@ -0,0 +1,35 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Enumerator#+" do
+    before :each do
+      ScratchPad.record []
+    end
+
+    it "returns a chain of self and provided enumerators" do
+      one   = Enumerator.new { |y| y << 1 }
+      two   = Enumerator.new { |y| y << 2 }
+      three = Enumerator.new { |y| y << 3 }
+
+      chain = one + two + three
+
+      chain.should be_an_instance_of(Enumerator::Chain)
+      chain.each { |item| ScratchPad << item }
+      ScratchPad.recorded.should == [1, 2, 3]
+    end
+
+    it "calls #each on each argument" do
+      enum = Enumerator.new { |y| y << "one" }
+
+      obj1 = mock("obj1")
+      obj1.should_receive(:each).once.and_yield("two")
+
+      obj2 = mock("obj2")
+      obj2.should_receive(:each).once.and_yield("three")
+
+      chain = enum + obj1 + obj2
+      chain.each { |item| ScratchPad << item }
+      ScratchPad.recorded.should == ["one", "two", "three"]
+    end
+  end
+end
diff --git a/spec/ruby/core/enumerator/rewind_spec.rb b/spec/ruby/core/enumerator/rewind_spec.rb
index e846f63c49..2a83b7c6ee 100644
--- a/spec/ruby/core/enumerator/rewind_spec.rb
+++ b/spec/ruby/core/enumerator/rewind_spec.rb
@@ -1,9 +1,41 @@
 require_relative '../../spec_helper'
-require_relative '../../shared/enumerator/rewind'
 require_relative 'fixtures/common'
 
 describe "Enumerator#rewind" do
-  it_behaves_like :enum_rewind, :rewind
+  before :each do
+    @enum = 1.upto(3)
+  end
+
+  it "resets the enumerator to its initial state" do
+    @enum.next.should == 1
+    @enum.next.should == 2
+    @enum.rewind
+    @enum.next.should == 1
+  end
+
+  it "returns self" do
+    @enum.rewind.should == @enum
+  end
+
+  it "has no effect on a new enumerator" do
+    @enum.rewind
+    @enum.next.should == 1
+  end
+
+  it "has no effect if called multiple, consecutive times" do
+    @enum.next.should == 1
+    @enum.rewind
+    @enum.rewind
+    @enum.next.should == 1
+  end
+
+  it "works with peek to reset the position" do
+    @enum.next
+    @enum.next
+    @enum.rewind
+    @enum.next
+    @enum.peek.should == 2
+  end
 
   it "calls the enclosed object's rewind method if one exists" do
     obj = mock('rewinder')
diff --git a/spec/ruby/core/env/filter_spec.rb b/spec/ruby/core/env/filter_spec.rb
new file mode 100644
index 0000000000..ba18a3b33b
--- /dev/null
+++ b/spec/ruby/core/env/filter_spec.rb
@@ -0,0 +1,15 @@
+require_relative '../../spec_helper'
+require_relative '../enumerable/shared/enumeratorized'
+require_relative 'shared/select'
+
+ruby_version_is "2.6" do
+  describe "ENV.filter!" do
+    it_behaves_like :env_select!, :filter!
+    it_behaves_like :enumeratorized_with_origin_size, :filter!, ENV
+  end
+
+  describe "ENV.filter" do
+    it_behaves_like :env_select, :filter
+    it_behaves_like :enumeratorized_with_origin_size, :filter, ENV
+  end
+end
diff --git a/spec/ruby/core/env/select_spec.rb b/spec/ruby/core/env/select_spec.rb
index 9ccd27f3e7..c3a76f4434 100644
--- a/spec/ruby/core/env/select_spec.rb
+++ b/spec/ruby/core/env/select_spec.rb
@@ -1,39 +1,13 @@
 require_relative '../../spec_helper'
 require_relative '../enumerable/shared/enumeratorized'
+require_relative 'shared/select'
 
 describe "ENV.select!" do
-  it "removes environment variables for which the block returns true" do
-    ENV["foo"] = "bar"
-    ENV.select! { |k, v| k != "foo" }
-    ENV["foo"].should == nil
-  end
-
-  it "returns self if any changes were made" do
-    ENV["foo"] = "bar"
-    ENV.select! { |k, v| k != "foo" }.should == ENV
-  end
-
-  it "returns nil if no changes were made" do
-    ENV.select! { true }.should == nil
-  end
-
-  it "returns an Enumerator if called without a block" do
-    ENV.select!.should be_an_instance_of(Enumerator)
-  end
-
+  it_behaves_like :env_select!, :select!
   it_behaves_like :enumeratorized_with_origin_size, :select!, ENV
 end
 
 describe "ENV.select" do
-  it "returns a Hash of names and values for which block return true" do
-    ENV["foo"] = "bar"
-    ENV.select { |k, v| k == "foo" }.should == {"foo" => "bar"}
-    ENV.delete "foo"
-  end
-
-  it "returns an Enumerator when no block is given" do
-    ENV.select.should be_an_instance_of(Enumerator)
-  end
-
+  it_behaves_like :env_select, :select
   it_behaves_like :enumeratorized_with_origin_size, :select, ENV
 end
diff --git a/spec/ruby/core/env/shared/select.rb b/spec/ruby/core/env/shared/select.rb
new file mode 100644
index 0000000000..a0b46a775a
--- /dev/null
+++ b/spec/ruby/core/env/shared/select.rb
@@ -0,0 +1,32 @@
+describe :env_select, shared: true do
+  it "returns a Hash of names and values for which block return true" do
+    ENV["foo"] = "bar"
+    (ENV.send(@method) { |k, v| k == "foo" }).should == { "foo" => "bar" }
+    ENV.delete "foo"
+  end
+
+  it "returns an Enumerator when no block is given" do
+    ENV.send(@method).should be_an_instance_of(Enumerator)
+  end
+end
+
+describe :env_select!, shared: true do
+  it "removes environment variables for which the block returns true" do
+    ENV["foo"] = "bar"
+    ENV.send(@method) { |k, v| k != "foo" }
+    ENV["foo"].should == nil
+  end
+
+  it "returns self if any changes were made" do
+    ENV["foo"] = "bar"
+    (ENV.send(@method) { |k, v| k != "foo" }).should == ENV
+  end
+
+  it "returns nil if no changes were made" do
+    (ENV.send(@method) { true }).should == nil
+  end
+
+  it "returns an Enumerator if called without a block" do
+    ENV.send(@method).should be_an_instance_of(Enumerator)
+  end
+end
diff --git a/spec/ruby/core/env/to_h_spec.rb b/spec/ruby/core/env/to_h_spec.rb
index f6c796b4d6..81a17700e9 100644
--- a/spec/ruby/core/env/to_h_spec.rb
+++ b/spec/ruby/core/env/to_h_spec.rb
@@ -1,18 +1,54 @@
 require_relative '../../spec_helper'
 require_relative 'shared/to_hash'
 
-describe "ENV.to_hash" do
+describe "ENV.to_h" do
   it_behaves_like :env_to_hash, :to_h
 
   ruby_version_is "2.6" do
-    it "converts [key, value] pairs returned by the block to a hash" do
-      orig = ENV.to_hash
-      begin
-        ENV.replace "a" => "b", "c" => "d"
-        i = 0
-        ENV.to_h {|k, v| [k.to_sym, v.upcase]}.should == {a:"B", c:"D"}
-      ensure
-        ENV.replace orig
+    context "with block" do
+      before do
+        @orig_hash = ENV.to_hash
+      end
+
+      after do
+        ENV.replace @orig_hash
+      end
+
+      it "converts [key, value] pairs returned by the block to a hash" do
+        ENV.replace("a" => "b", "c" => "d")
+        ENV.to_h { |k, v| [k, v.upcase] }.should == { 'a' => "B", 'c' => "D" }
+      end
+
+      it "raises ArgumentError if block returns longer or shorter array" do
+        -> do
+          ENV.to_h { |k, v| [k, v.upcase, 1] }
+        end.should raise_error(ArgumentError, /element has wrong array length/)
+
+        -> do
+          ENV.to_h { |k, v| [k] }
+        end.should raise_error(ArgumentError, /element has wrong array length/)
+      end
+
+      it "raises TypeError if block returns something other than Array" do
+        -> do
+          ENV.to_h { |k, v| "not-array" }
+        end.should raise_error(TypeError, /wrong element type String/)
+      end
+
+      it "coerces returned pair to Array with #to_ary" do
+        x = mock('x')
+        x.stub!(:to_ary).and_return([:b, 'b'])
+
+        ENV.to_h { |k| x }.should == { :b => 'b' }
+      end
+
+      it "does not coerce returned pair to Array with #to_a" do
+        x = mock('x')
+        x.stub!(:to_a).and_return([:b, 'b'])
+
+        -> do
+          ENV.to_h { |k| x }
+        end.should raise_error(TypeError, /wrong element type MockObject/)
       end
     end
   end
diff --git a/spec/ruby/core/exception/full_message_spec.rb b/spec/ruby/core/exception/full_message_spec.rb
index f56282d67b..bc611c165b 100644
--- a/spec/ruby/core/exception/full_message_spec.rb
+++ b/spec/ruby/core/exception/full_message_spec.rb
@@ -34,5 +34,42 @@ ruby_version_is "2.5" do
         e.full_message(order: :bottom, highlight: false).should =~ /b.rb:2.*a.rb:1/m
       end
     end
+
+    ruby_version_is "2.6" do
+      it "contains cause of exception" do
+        begin
+          begin
+            raise 'the cause'
+          rescue
+            raise 'main exception'
+          end
+        rescue => e
+          exception = e
+        end
+
+        exception.full_message.should include "main exception"
+        exception.full_message.should include "the cause"
+      end
+
+      it 'contains all the chain of exceptions' do
+        begin
+          begin
+            begin
+              raise 'origin exception'
+            rescue
+              raise 'intermediate exception'
+            end
+          rescue
+            raise 'last exception'
+          end
+        rescue => e
+          exception = e
+        end
+
+        exception.full_message.should include "last exception"
+        exception.full_message.should include "intermediate exception"
+        exception.full_message.should include "origin exception"
+      end
+    end
   end
 end
diff --git a/spec/ruby/core/exception/key_error_spec.rb b/spec/ruby/core/exception/key_error_spec.rb
new file mode 100644
index 0000000000..ad280279d8
--- /dev/null
+++ b/spec/ruby/core/exception/key_error_spec.rb
@@ -0,0 +1,15 @@
+require_relative '../../spec_helper'
+
+describe "KeyError" do
+  ruby_version_is "2.6" do
+    it "accepts :receiver and :key options" do
+      receiver = mock("receiver")
+      key = mock("key")
+
+      error = KeyError.new(receiver: receiver, key: key)
+
+      error.receiver.should == receiver
+      error.key.should == key
+    end
+  end
+end
diff --git a/spec/ruby/core/exception/name_error_spec.rb b/spec/ruby/core/exception/name_error_spec.rb
index a5810f178f..d0a810029b 100644
--- a/spec/ruby/core/exception/name_error_spec.rb
+++ b/spec/ruby/core/exception/name_error_spec.rb
@@ -10,4 +10,15 @@ describe "NameError.new" do
   it "should take optional name argument" do
     NameError.new("msg","name").name.should == "name"
   end
+
+  ruby_version_is "2.6" do
+    it "accepts a :receiver keyword argument" do
+      receiver = mock("receiver")
+
+      error = NameError.new("msg", :name, receiver: receiver)
+
+      error.receiver.should == receiver
+      error.name.should == :name
+    end
+  end
 end
diff --git a/spec/ruby/core/exception/no_method_error_spec.rb b/spec/ruby/core/exception/no_method_error_spec.rb
index 7839c080a8..28c3549562 100644
--- a/spec/ruby/core/exception/no_method_error_spec.rb
+++ b/spec/ruby/core/exception/no_method_error_spec.rb
@@ -3,12 +3,23 @@ require_relative 'fixtures/common'
 
 describe "NoMethodError.new" do
   it "allows passing method args" do
-    NoMethodError.new("msg","name","args").args.should == "args"
+    NoMethodError.new("msg", "name", ["args"]).args.should == ["args"]
   end
 
   it "does not require a name" do
     NoMethodError.new("msg").message.should == "msg"
   end
+
+  ruby_version_is "2.6" do
+    it "accepts a :receiver keyword argument" do
+      receiver = mock("receiver")
+
+      error = NoMethodError.new("msg", :name, receiver: receiver)
+
+      error.receiver.should == receiver
+      error.name.should == :name
+    end
+  end
 end
 
 describe "NoMethodError#args" do
diff --git a/spec/ruby/core/file/open_spec.rb b/spec/ruby/core/file/open_spec.rb
index c6a0b68233..c37e7316ba 100644
--- a/spec/ruby/core/file/open_spec.rb
+++ b/spec/ruby/core/file/open_spec.rb
@@ -638,6 +638,33 @@ describe "File.open" do
     end
   end
 
+  ruby_version_is "2.6" do
+    context "'x' flag" do
+      before :each do
+        @xfile = tmp("x-flag")
+        rm_r @xfile
+      end
+
+      after :each do
+        rm_r @xfile
+      end
+
+      it "does nothing if the file doesn't exist" do
+        File.open(@xfile, "wx") { |f| f.write("content") }
+        File.read(@xfile).should == "content"
+      end
+
+      it "throws a Errno::EEXIST error if the file exists" do
+        touch @xfile
+        lambda { File.open(@xfile, "wx") }.should raise_error(Errno::EEXIST)
+      end
+
+      it "can't be used with 'r' and 'a' flags" do
+        lambda { File.open(@xfile, "rx") }.should raise_error(ArgumentError, 'invalid access mode rx')
+        lambda { File.open(@xfile, "ax") }.should raise_error(ArgumentError, 'invalid access mode ax')
+      end
+    end
+  end
 end
 
 describe "File.open when passed a file descriptor" do
diff --git a/spec/ruby/core/hash/merge_spec.rb b/spec/ruby/core/hash/merge_spec.rb
index 3af1ea6d4f..5ea70610be 100644
--- a/spec/ruby/core/hash/merge_spec.rb
+++ b/spec/ruby/core/hash/merge_spec.rb
@@ -63,6 +63,17 @@ describe "Hash#merge" do
     merge_pairs.should == each_pairs
   end
 
+  ruby_version_is "2.6" do
+    it "accepts multiple hashes" do
+      result = { a: 1 }.merge({ b: 2 }, { c: 3 }, { d: 4 })
+      result.should == { a: 1, b: 2, c: 3, d: 4 }
+    end
+
+    it "accepts zero arguments and returns self" do
+      hash = { a: 1 }
+      hash.merge.should eql(hash)
+    end
+  end
 end
 
 describe "Hash#merge!" do
diff --git a/spec/ruby/core/hash/shared/update.rb b/spec/ruby/core/hash/shared/update.rb
index be03ac019e..250c5ab440 100644
--- a/spec/ruby/core/hash/shared/update.rb
+++ b/spec/ruby/core/hash/shared/update.rb
@@ -56,4 +56,16 @@ describe :hash_update, shared: true do
       HashSpecs.frozen_hash.send(@method, HashSpecs.empty_frozen_hash)
     end.should raise_error(frozen_error_class)
   end
+
+  ruby_version_is "2.6" do
+    it "accepts multiple hashes" do
+      result = { a: 1 }.send(@method, { b: 2 }, { c: 3 }, { d: 4 })
+      result.should == { a: 1, b: 2, c: 3, d: 4 }
+    end
+
+    it "accepts zero arguments" do
+      hash = { a: 1 }
+      hash.send(@method).should eql(hash)
+    end
+  end
 end
diff --git a/spec/ruby/core/hash/to_h_spec.rb b/spec/ruby/core/hash/to_h_spec.rb
index 40bd0d06d2..d6eaac9f33 100644
--- a/spec/ruby/core/hash/to_h_spec.rb
+++ b/spec/ruby/core/hash/to_h_spec.rb
@@ -7,12 +7,6 @@ describe "Hash#to_h" do
     h.to_h.should equal(h)
   end
 
-  ruby_version_is "2.6" do
-    it "converts [key, value] pairs returned by the block to a hash" do
-      {a: 1, b: 2}.to_h {|k, v| [k.to_s, v*v]}.should == { "a" => 1, "b" => 4 }
-    end
-  end
-
   describe "when called on a subclass of Hash" do
     before :each do
       @h = HashSpecs::MyHash.new
@@ -37,4 +31,44 @@ describe "Hash#to_h" do
       @h[42].should == 84
     end
   end
+
+  ruby_version_is "2.6" do
+    context "with block" do
+      it "converts [key, value] pairs returned by the block to a hash" do
+        { a: 1, b: 2 }.to_h { |k, v| [k.to_s, v*v]}.should == { "a" => 1, "b" => 4 }
+      end
+
+      it "raises ArgumentError if block returns longer or shorter array" do
+        -> do
+          { a: 1, b: 2 }.to_h { |k, v| [k.to_s, v*v, 1] }
+        end.should raise_error(ArgumentError, /element has wrong array length/)
+
+        -> do
+          { a: 1, b: 2 }.to_h { |k, v| [k] }
+        end.should raise_error(ArgumentError, /element has wrong array length/)
+      end
+
+      it "raises TypeError if block returns something other than Array" do
+        -> do
+          { a: 1, b: 2 }.to_h { |k, v| "not-array" }
+        end.should raise_error(TypeError, /wrong element type String/)
+      end
+
+      it "coerces returned pair to Array with #to_ary" do
+        x = mock('x')
+        x.stub!(:to_ary).and_return([:b, 'b'])
+
+        { a: 1 }.to_h { |k| x }.should == { :b => 'b' }
+      end
+
+      it "does not coerce returned pair to Array with #to_a" do
+        x = mock('x')
+        x.stub!(:to_a).and_return([:b, 'b'])
+
+        -> do
+          { a: 1 }.to_h { |k| x }
+        end.should raise_error(TypeError, /wrong element type MockObject/)
+      end
+    end
+  end
 end
diff --git a/spec/ruby/core/io/ungetbyte_spec.rb b/spec/ruby/core/io/ungetbyte_spec.rb
index 2e51fb0298..f5f9a11be1 100644
--- a/spec/ruby/core/io/ungetbyte_spec.rb
+++ b/spec/ruby/core/io/ungetbyte_spec.rb
@@ -49,7 +49,7 @@ describe "IO#ungetbyte" do
     end
   end
 
-  ruby_version_is '2.6'...'2.7' do
+  ruby_version_is '2.6'...'2.6.1' do
     it "is an RangeError if the integer is not in 8bit" do
       for i in [4095, 0x4f7574206f6620636861722072616e6765] do
         lambda { @io.ungetbyte(i) }.should raise_error(RangeError)
@@ -57,10 +57,11 @@ describe "IO#ungetbyte" do
     end
   end
 
-  ruby_version_is '2.7' do
+  ruby_version_is '2.6.1' do
     it "never raises RangeError" do
-      for i in [4095, 0x4f7574206f6620636861722072616e6765] do
-        lambda { @io.ungetbyte(i) }.should_not raise_error
+      for i in [4095, 0x4f7574206f6620636861722072616e67ff] do
+        @io.ungetbyte(i).should be_nil
+        @io.getbyte.should == 255
       end
     end
   end
diff --git a/spec/ruby/core/kernel/Complex_spec.rb b/spec/ruby/core/kernel/Complex_spec.rb
index 44e4f44ada..e5435a56e6 100644
--- a/spec/ruby/core/kernel/Complex_spec.rb
+++ b/spec/ruby/core/kernel/Complex_spec.rb
@@ -138,4 +138,52 @@ describe "Kernel.Complex()" do
       lambda { Complex(nil, 0) }.should raise_error(TypeError, "can't convert nil into Complex")
     end
   end
+
+  ruby_version_is "2.6" do
+    describe "when passed exception: false" do
+      describe "and [Numeric]" do
+        it "returns a complex number" do
+          Complex("123", exception: false).should == Complex(123)
+        end
+      end
+
+      describe "and [non-Numeric]" do
+        it "swallows an error" do
+          Complex(:sym, exception: false).should == nil
+        end
+      end
+
+      describe "and [non-Numeric, Numeric] argument" do
+        it "throws a TypeError" do
+          lambda { Complex(:sym, 0, exception: false) }.should raise_error(TypeError, "not a real")
+        end
+      end
+
+      describe "and [anything, non-Numeric] argument" do
+        it "swallows an error" do
+          Complex("a",  :sym, exception: false).should == nil
+          Complex(:sym, :sym, exception: false).should == nil
+          Complex(0,    :sym, exception: false).should == nil
+        end
+      end
+
+      describe "and non-numeric String arguments" do
+        it "swallows an error" do
+          Complex("a", "b", exception: false).should == nil
+          Complex("a", 0, exception: false).should == nil
+          Complex(0, "b", exception: false).should == nil
+        end
+      end
+
+      ruby_bug "#15525", "2.6"..."2.6.1" do
+        describe "and nil arguments" do
+          it "swallows an error" do
+            Complex(nil, exception: false).should == nil
+            Complex(0, nil, exception: false).should == nil
+            Complex(nil, 0, exception: false).should == nil
+          end
+        end
+      end
+    end
+  end
 end
diff --git a/spec/ruby/core/kernel/Float_spec.rb b/spec/ruby/core/kernel/Float_spec.rb
index 47d7d0816f..43daefa6aa 100644
--- a/spec/ruby/core/kernel/Float_spec.rb
+++ b/spec/ruby/core/kernel/Float_spec.rb
@@ -299,6 +299,31 @@ describe :kernel_float, shared: true do
     c = Complex(2, 3)
     lambda { @object.send(:Float, c) }.should raise_error(RangeError)
   end
+
+  ruby_version_is "2.6" do
+    describe "when passed exception: false" do
+      describe "and valid input" do
+        it "returns a Float number" do
+          @object.send(:Float, 1, exception: false).should == 1.0
+          @object.send(:Float, "1", exception: false).should == 1.0
+          @object.send(:Float, "1.23", exception: false).should == 1.23
+        end
+      end
+
+      describe "and invalid input" do
+        it "swallows an error" do
+          @object.send(:Float, "abc", exception: false).should == nil
+          @object.send(:Float, :sym, exception: false).should == nil
+        end
+      end
+
+      describe "and nil" do
+        it "swallows it" do
+          @object.send(:Float, nil, exception: false).should == nil
+        end
+      end
+    end
+  end
 end
 
 describe "Kernel.Float" do
diff --git a/spec/ruby/core/kernel/Integer_spec.rb b/spec/ruby/core/kernel/Integer_spec.rb
index b79c827d31..72e33fc737 100644
--- a/spec/ruby/core/kernel/Integer_spec.rb
+++ b/spec/ruby/core/kernel/Integer_spec.rb
@@ -99,6 +99,65 @@ describe :kernel_integer, shared: true do
   it "raises a FloatDomainError when passed Infinity" do
     lambda { Integer(infinity_value) }.should raise_error(FloatDomainError)
   end
+
+  ruby_version_is "2.6" do
+    describe "when passed exception: false" do
+      describe "and to_i returns a value that is not an Integer" do
+        it "swallows an error" do
+          obj = mock("object")
+          obj.should_receive(:to_i).and_return("1")
+          Integer(obj, exception: false).should == nil
+        end
+      end
+
+      describe "and no to_int or to_i methods exist" do
+        it "swallows an error" do
+          obj = mock("object")
+          Integer(obj, exception: false).should == nil
+        end
+      end
+
+      describe "and to_int returns nil and no to_i exists" do
+        it "swallows an error" do
+          obj = mock("object")
+          obj.should_receive(:to_i).and_return(nil)
+          Integer(obj, exception: false).should == nil
+        end
+      end
+
+      ruby_bug "#15525", "2.6"..."2.6.1" do
+        describe "and passed NaN" do
+          it "swallows an error" do
+            Integer(nan_value, exception: false).should == nil
+          end
+        end
+
+        describe "and passed Infinity" do
+          it "swallows an error" do
+            Integer(infinity_value, exception: false).should == nil
+          end
+        end
+      end
+
+      describe "and passed nil" do
+        it "swallows an error" do
+          Integer(nil, exception: false).should == nil
+        end
+      end
+
+      describe "and passed a String that contains numbers" do
+        it "normally parses it and returns an Integer" do
+          Integer("42", exception: false).should == 42
+        end
+      end
+
+      describe "and passed a String that can't be converted to an Integer" do
+        it "swallows an error" do
+          Integer("abc", exception: false).should == nil
+        end
+      end
+    end
+  end
 end
 
 describe "Integer() given a String", shared: true do
@@ -189,6 +248,34 @@ describe "Integer() given a String", shared: true do
     lambda { Integer("") }.should raise_error(ArgumentError)
   end
 
+  ruby_version_is "2.6" do
+    describe "when passed exception: false" do
+      describe "and multiple leading -s" do
+        it "swallows an error" do
+          Integer("---1", exception: false).should == nil
+        end
+      end
+
+      describe "and multiple trailing -s" do
+        it "swallows an error" do
+          Integer("1---", exception: false).should == nil
+        end
+      end
+
+      describe "and an argument that contains a period" do
+        it "swallows an error" do
+          Integer("0.0", exception: false).should == nil
+        end
+      end
+
+      describe "and an empty string" do
+        it "swallows an error" do
+          Integer("", exception: false).should == nil
+        end
+      end
+    end
+  end
+
   it "parses the value as 0 if the string consists of a single zero character" do
     Integer("0").should == 0
   end
@@ -508,6 +595,24 @@ describe "Integer() given a String and base", shared: true do
       lambda { Integer(98, 15) }.should raise_error(ArgumentError)
     end
   end
+
+  ruby_version_is "2.6" do
+    describe "when passed exception: false" do
+      describe "and valid argument" do
+        it "returns an Integer number" do
+          Integer("100", 10, exception: false).should == 100
+          Integer("100", 2, exception: false).should == 4
+        end
+      end
+
+      describe "and invalid argument" do
+        it "swallows an error" do
+          Integer("999", 2, exception: false).should == nil
+          Integer("abc", 10, exception: false).should == nil
+        end
+      end
+    end
+  end
 end
 
 describe :kernel_Integer, shared: true do
diff --git a/spec/ruby/core/kernel/match_spec.rb b/spec/ruby/core/kernel/match_spec.rb
index d5808b6ede..6dc1eb7de8 100644
--- a/spec/ruby/core/kernel/match_spec.rb
+++ b/spec/ruby/core/kernel/match_spec.rb
@@ -13,4 +13,12 @@ describe "Kernel#=~" do
       (o =~ true).should       be_nil
     end
   end
+
+  ruby_version_is "2.6" do
+    it "is deprecated" do
+      -> do
+        Object.new =~ /regexp/
+      end.should complain(/deprecated Object#=~ is called on Object/, verbose: true)
+    end
+  end
 end
diff --git a/spec/ruby/core/kernel/shared/load.rb b/spec/ruby/core/kernel/shared/load.rb
index 0ce7d58d2c..b479b29399 100644
--- a/spec/ruby/core/kernel/shared/load.rb
+++ b/spec/ruby/core/kernel/shared/load.rb
@@ -30,9 +30,8 @@ describe :kernel_load, shared: true do
   it "loads a file that recursively requires itself" do
     path = File.expand_path "recursive_require_fixture.rb", CODE_LOADING_DIR
     -> {
-      $VERBOSE = true
       @object.load(path).should be_true
-    }.should complain(/circular require considered harmful/)
+    }.should complain(/circular require considered harmful/, verbose: true)
     ScratchPad.recorded.should == [:loaded, :loaded]
   end
 
diff --git a/spec/ruby/core/kernel/shared/require.rb b/spec/ruby/core/kernel/shared/require.rb
index a81a68088a..b502476bc3 100644
--- a/spec/ruby/core/kernel/shared/require.rb
+++ b/spec/ruby/core/kernel/shared/require.rb
@@ -225,9 +225,8 @@ describe :kernel_require, shared: true do
     it "loads a file that recursively requires itself" do
       path = File.expand_path "recursive_require_fixture.rb", CODE_LOADING_DIR
       -> {
-        $VERBOSE = true
         @object.require(path).should be_true
-      }.should complain(/circular require considered harmful/)
+      }.should complain(/circular require considered harmful/, verbose: true)
       ScratchPad.recorded.should == [:loaded]
     end
   end
diff --git a/spec/ruby/core/method/compose_spec.rb b/spec/ruby/core/method/compose_spec.rb
new file mode 100644
index 0000000000..aa0aded775
--- /dev/null
+++ b/spec/ruby/core/method/compose_spec.rb
@@ -0,0 +1,101 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+require_relative '../proc/shared/compose'
+
+ruby_version_is "2.6" do
+  describe "Method#<<" do
+    it "returns a Proc that is the composition of self and the passed Proc" do
+      succ = MethodSpecs::Composition.new.method(:succ)
+      upcase = proc { |s| s.upcase }
+
+      (succ << upcase).call('Ruby').should == "RUBZ"
+    end
+
+    it "calls passed Proc with arguments and then calls self with result" do
+      pow_2_proc = proc { |x| x * x }
+      double_proc = proc { |x| x + x }
+
+      pow_2_method = MethodSpecs::Composition.new.method(:pow_2)
+      double_method = MethodSpecs::Composition.new.method(:double)
+
+      (pow_2_method << double_proc).call(2).should == 16
+      (double_method << pow_2_proc).call(2).should == 8
+    end
+
+    it "accepts any callable object" do
+      inc = MethodSpecs::Composition.new.method(:inc)
+
+      double = Object.new
+      def double.call(n); n * 2; end
+
+      (inc << double).call(3).should == 7
+    end
+
+    it_behaves_like :proc_compose, :<<, -> { MethodSpecs::Composition.new.method(:upcase) }
+
+    describe "composition" do
+      it "is a lambda" do
+        pow_2 = MethodSpecs::Composition.new.method(:pow_2)
+        double = proc { |x| x + x }
+
+        (pow_2 << double).is_a?(Proc).should == true
+        (pow_2 << double).lambda?.should == true
+      end
+
+      it "may accept multiple arguments" do
+        inc = MethodSpecs::Composition.new.method(:inc)
+        mul = proc { |n, m| n * m }
+
+        (inc << mul).call(2, 3).should == 7
+      end
+    end
+  end
+
+  describe "Method#>>" do
+    it "returns a Proc that is the composition of self and the passed Proc" do
+      upcase = proc { |s| s.upcase }
+      succ = MethodSpecs::Composition.new.method(:succ)
+
+      (succ >> upcase).call('Ruby').should == "RUBZ"
+    end
+
+    it "calls passed Proc with arguments and then calls self with result" do
+      pow_2_proc = proc { |x| x * x }
+      double_proc = proc { |x| x + x }
+
+      pow_2_method = MethodSpecs::Composition.new.method(:pow_2)
+      double_method = MethodSpecs::Composition.new.method(:double)
+
+      (pow_2_method >> double_proc).call(2).should == 8
+      (double_method >> pow_2_proc).call(2).should == 16
+    end
+
+    it "accepts any callable object" do
+      inc = MethodSpecs::Composition.new.method(:inc)
+
+      double = Object.new
+      def double.call(n); n * 2; end
+
+      (inc >> double).call(3).should == 8
+    end
+
+    it_behaves_like :proc_compose, :>>, -> { MethodSpecs::Composition.new.method(:upcase) }
+
+    describe "composition" do
+      it "is a lambda" do
+        pow_2 = MethodSpecs::Composition.new.method(:pow_2)
+        double = proc { |x| x + x }
+
+        (pow_2 >> double).is_a?(Proc).should == true
+        (pow_2 >> double).lambda?.should == true
+      end
+
+      it "may accept multiple arguments" do
+        mul = MethodSpecs::Composition.new.method(:mul)
+        inc = proc { |n| n + 1 }
+
+        (mul >> inc).call(2, 3).should == 7
+      end
+    end
+  end
+end
diff --git a/spec/ruby/core/method/fixtures/classes.rb b/spec/ruby/core/method/fixtures/classes.rb
index 142cbd1bec..315672c6e0 100644
--- a/spec/ruby/core/method/fixtures/classes.rb
+++ b/spec/ruby/core/method/fixtures/classes.rb
@@ -181,4 +181,29 @@ module MethodSpecs
     end
   end
 
+  class Composition
+    def upcase(s)
+      s.upcase
+    end
+
+    def succ(s)
+      s.succ
+    end
+
+    def pow_2(n)
+      n * n
+    end
+
+    def double(n)
+      n + n
+    end
+
+    def inc(n)
+      n + 1
+    end
+
+    def mul(n, m)
+      n * m
+    end
+  end
 end
diff --git a/spec/ruby/core/module/attr_spec.rb b/spec/ruby/core/module/attr_spec.rb
index 87bf8ea57f..b114b06b6e 100644
--- a/spec/ruby/core/module/attr_spec.rb
+++ b/spec/ruby/core/module/attr_spec.rb
@@ -138,9 +138,8 @@ describe "Module#attr" do
 
   it "with a boolean argument emits a warning when $VERBOSE is true" do
     lambda {
-      $VERBOSE = true
       Class.new { attr :foo, true }
-    }.should complain(/boolean argument is obsoleted/)
+    }.should complain(/boolean argument is obsoleted/, verbose: true)
   end
 
   ruby_version_is ''...'2.5' do
diff --git a/spec/ruby/core/module/autoload_spec.rb b/spec/ruby/core/module/autoload_spec.rb
index d6af169cff..b028dbc56c 100644
--- a/spec/ruby/core/module/autoload_spec.rb
+++ b/spec/ruby/core/module/autoload_spec.rb
@@ -582,9 +582,8 @@ describe "Module#autoload" do
     end
 
     -> {
-      $VERBOSE = true
       Kernel.require fixture(__FILE__, "autoload_during_require.rb")
-    }.should_not complain
+    }.should_not complain(verbose: true)
     ModuleSpecs::Autoload::AutoloadDuringRequire.should be_kind_of(Class)
   end
 
diff --git a/spec/ruby/core/module/method_defined_spec.rb b/spec/ruby/core/module/method_defined_spec.rb
index 62e0db8ee6..f5203917b4 100644
--- a/spec/ruby/core/module/method_defined_spec.rb
+++ b/spec/ruby/core/module/method_defined_spec.rb
@@ -46,4 +46,55 @@ describe "Module#method_defined?" do
 
     c.method_defined?(o).should == true
   end
+
+  ruby_version_is "2.6" do
+    # works as method_defined?(method_name)
+    describe "when passed true as a second optional argument" do
+      it "performs a lookup in ancestors" do
+        ModuleSpecs::Child.method_defined?(:public_child, true).should == true
+        ModuleSpecs::Child.method_defined?(:protected_child, true).should == true
+        ModuleSpecs::Child.method_defined?(:accessor_method, true).should == true
+        ModuleSpecs::Child.method_defined?(:private_child, true).should == false
+
+        # Defined in Parent
+        ModuleSpecs::Child.method_defined?(:public_parent, true).should == true
+        ModuleSpecs::Child.method_defined?(:protected_parent, true).should == true
+        ModuleSpecs::Child.method_defined?(:private_parent, true).should == false
+
+        # Defined in Module
+        ModuleSpecs::Child.method_defined?(:public_module, true).should == true
+        ModuleSpecs::Child.method_defined?(:protected_module, true).should == true
+        ModuleSpecs::Child.method_defined?(:private_module, true).should == false
+
+        # Defined in SuperModule
+        ModuleSpecs::Child.method_defined?(:public_super_module, true).should == true
+        ModuleSpecs::Child.method_defined?(:protected_super_module, true).should == true
+        ModuleSpecs::Child.method_defined?(:private_super_module, true).should == false
+      end
+    end
+
+    describe "when passed false as a second optional argument" do
+      it "checks only the class itself" do
+        ModuleSpecs::Child.method_defined?(:public_child, false).should == true
+        ModuleSpecs::Child.method_defined?(:protected_child, false).should == true
+        ModuleSpecs::Child.method_defined?(:accessor_method, false).should == true
+        ModuleSpecs::Child.method_defined?(:private_child, false).should == false
+
+        # Defined in Parent
+        ModuleSpecs::Child.method_defined?(:public_parent, false).should == false
+        ModuleSpecs::Child.method_defined?(:protected_parent, false).should == false
+        ModuleSpecs::Child.method_defined?(:private_parent, false).should == false
+
+        # Defined in Module
+        ModuleSpecs::Child.method_defined?(:public_module, false).should == false
+        ModuleSpecs::Child.method_defined?(:protected_module, false).should == false
+        ModuleSpecs::Child.method_defined?(:private_module, false).should == false
+
+        # Defined in SuperModule
+        ModuleSpecs::Child.method_defined?(:public_super_module, false).should == false
+        ModuleSpecs::Child.method_defined?(:protected_super_module, false).should == false
+        ModuleSpecs::Child.method_defined?(:private_super_module, false).should == false
+      end
+    end
+  end
 end
diff --git a/spec/ruby/core/module/private_method_defined_spec.rb b/spec/ruby/core/module/private_method_defined_spec.rb
index e00a8c8a9b..a3cf55852e 100644
--- a/spec/ruby/core/module/private_method_defined_spec.rb
+++ b/spec/ruby/core/module/private_method_defined_spec.rb
@@ -69,4 +69,54 @@ describe "Module#private_method_defined?" do
     def str.to_str() 'private_3' end
     ModuleSpecs::CountsMixin.private_method_defined?(str).should == true
   end
+
+  ruby_version_is "2.6" do
+    describe "when passed true as a second optional argument" do
+      it "performs a lookup in ancestors" do
+        ModuleSpecs::Child.private_method_defined?(:public_child, true).should == false
+        ModuleSpecs::Child.private_method_defined?(:protected_child, true).should == false
+        ModuleSpecs::Child.private_method_defined?(:accessor_method, true).should == false
+        ModuleSpecs::Child.private_method_defined?(:private_child, true).should == true
+
+        # Defined in Parent
+        ModuleSpecs::Child.private_method_defined?(:public_parent, true).should == false
+        ModuleSpecs::Child.private_method_defined?(:protected_parent, true).should == false
+        ModuleSpecs::Child.private_method_defined?(:private_parent, true).should == true
+
+        # Defined in Module
+        ModuleSpecs::Child.private_method_defined?(:public_module, true).should == false
+        ModuleSpecs::Child.private_method_defined?(:protected_module, true).should == false
+        ModuleSpecs::Child.private_method_defined?(:private_module, true).should == true
+
+        # Defined in SuperModule
+        ModuleSpecs::Child.private_method_defined?(:public_super_module, true).should == false
+        ModuleSpecs::Child.private_method_defined?(:protected_super_module, true).should == false
+        ModuleSpecs::Child.private_method_defined?(:private_super_module, true).should == true
+      end
+    end
+
+    describe "when passed false as a second optional argument" do
+      it "checks only the class itself" do
+        ModuleSpecs::Child.private_method_defined?(:public_child, false).should == false
+        ModuleSpecs::Child.private_method_defined?(:protected_child, false).should == false
+        ModuleSpecs::Child.private_method_defined?(:accessor_method, false).should == false
+        ModuleSpecs::Child.private_method_defined?(:private_child, false).should == true
+
+        # Defined in Parent
+        ModuleSpecs::Child.private_method_defined?(:public_parent, false).should == false
+        ModuleSpecs::Child.private_method_defined?(:protected_parent, false).should == false
+        ModuleSpecs::Child.private_method_defined?(:private_parent, false).should == false
+
+        # Defined in Module
+        ModuleSpecs::Child.private_method_defined?(:public_module, false).should == false
+        ModuleSpecs::Child.private_method_defined?(:protected_module, false).should == false
+        ModuleSpecs::Child.private_method_defined?(:private_module, false).should == false
+
+        # Defined in SuperModule
+        ModuleSpecs::Child.private_method_defined?(:public_super_module, false).should == false
+        ModuleSpecs::Child.private_method_defined?(:protected_super_module, false).should == false
+        ModuleSpecs::Child.private_method_defined?(:private_super_module, false).should == false
+      end
+    end
+  end
 end
diff --git a/spec/ruby/core/module/protected_method_defined_spec.rb b/spec/ruby/core/module/protected_method_defined_spec.rb
index 8492a497d3..75e02e0433 100644
--- a/spec/ruby/core/module/protected_method_defined_spec.rb
+++ b/spec/ruby/core/module/protected_method_defined_spec.rb
@@ -69,4 +69,54 @@ describe "Module#protected_method_defined?" do
     str.should_receive(:to_str).and_return("protected_3")
     ModuleSpecs::CountsMixin.protected_method_defined?(str).should == true
   end
+
+  ruby_version_is "2.6" do
+    describe "when passed true as a second optional argument" do
+      it "performs a lookup in ancestors" do
+        ModuleSpecs::Child.protected_method_defined?(:public_child, true).should == false
+        ModuleSpecs::Child.protected_method_defined?(:protected_child, true).should == true
+        ModuleSpecs::Child.protected_method_defined?(:accessor_method, true).should == false
+        ModuleSpecs::Child.protected_method_defined?(:private_child, true).should == false
+
+        # Defined in Parent
+        ModuleSpecs::Child.protected_method_defined?(:public_parent, true).should == false
+        ModuleSpecs::Child.protected_method_defined?(:protected_parent, true).should == true
+        ModuleSpecs::Child.protected_method_defined?(:private_parent, true).should == false
+
+        # Defined in Module
+        ModuleSpecs::Child.protected_method_defined?(:public_module, true).should == false
+        ModuleSpecs::Child.protected_method_defined?(:protected_module, true).should == true
+        ModuleSpecs::Child.protected_method_defined?(:private_module, true).should == false
+
+        # Defined in SuperModule
+        ModuleSpecs::Child.protected_method_defined?(:public_super_module, true).should == false
+        ModuleSpecs::Child.protected_method_defined?(:protected_super_module, true).should == true
+        ModuleSpecs::Child.protected_method_defined?(:private_super_module, true).should == false
+      end
+    end
+
+    describe "when passed false as a second optional argument" do
+      it "checks only the class itself" do
+        ModuleSpecs::Child.protected_method_defined?(:public_child, false).should == false
+        ModuleSpecs::Child.protected_method_defined?(:protected_child, false).should == true
+        ModuleSpecs::Child.protected_method_defined?(:accessor_method, false).should == false
+        ModuleSpecs::Child.protected_method_defined?(:private_child, false).should == false
+
+        # Defined in Parent
+        ModuleSpecs::Child.protected_method_defined?(:public_parent, false).should == false
+        ModuleSpecs::Child.protected_method_defined?(:protected_parent, false).should == false
+        ModuleSpecs::Child.protected_method_defined?(:private_parent, false).should == false
+
+        # Defined in Module
+        ModuleSpecs::Child.protected_method_defined?(:public_module, false).should == false
+        ModuleSpecs::Child.protected_method_defined?(:protected_module, false).should == false
+        ModuleSpecs::Child.protected_method_defined?(:private_module, false).should == false
+
+        # Defined in SuperModule
+        ModuleSpecs::Child.protected_method_defined?(:public_super_module, false).should == false
+        ModuleSpecs::Child.protected_method_defined?(:protected_super_module, false).should == false
+        ModuleSpecs::Child.protected_method_defined?(:private_super_module, false).should == false
+      end
+    end
+  end
 end
diff --git a/spec/ruby/core/module/refine_spec.rb b/spec/ruby/core/module/refine_spec.rb
index 97ea0a706d..662d49205d 100644
--- a/spec/ruby/core/module/refine_spec.rb
+++ b/spec/ruby/core/module/refine_spec.rb
@@ -425,6 +425,24 @@ describe "Module#refine" do
       end
     end
 
+    ruby_version_is "" ... "2.6" do
+      it "is not honored by Kernel#public_send" do
+        refinement = Module.new do
+          refine ModuleSpecs::ClassWithFoo do
+            def foo; "foo from refinement"; end
+          end
+        end
+
+        result = nil
+        Module.new do
+          using refinement
+          result = ModuleSpecs::ClassWithFoo.new.public_send :foo
+        end
+
+        result.should == "foo"
+      end
+    end
+
     ruby_version_is "2.6" do
       it "is honored by Kernel#public_send" do
         refinement = Module.new do
@@ -561,6 +579,45 @@ describe "Module#refine" do
         result.should == true
       end
     end
+
+    ruby_version_is ""..."2.6" do
+      it "is not honored by &" do
+        refinement = Module.new do
+          refine String do
+            def to_proc(*args)
+              -> (*) { 'foo' }
+            end
+          end
+        end
+
+        -> do
+          Module.new do
+            using refinement
+            ["hola"].map(&"upcase")
+          end
+        end.should raise_error(TypeError, /wrong argument type String \(expected Proc\)/)
+      end
+    end
+
+    ruby_version_is "2.6" do
+      it "is honored by &" do
+        refinement = Module.new do
+          refine String do
+            def to_proc(*args)
+              -> (*) { 'foo' }
+            end
+          end
+        end
+
+        result = nil
+        Module.new do
+          using refinement
+          result = ["hola"].map(&"upcase")
+        end
+
+        result.should == ['foo']
+      end
+    end
   end
 
   context "when super is called in a refinement" do
diff --git a/spec/ruby/core/nil/match_spec.rb b/spec/ruby/core/nil/match_spec.rb
new file mode 100644
index 0000000000..3f69312bfe
--- /dev/null
+++ b/spec/ruby/core/nil/match_spec.rb
@@ -0,0 +1,19 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "NilClass#=~" do
+    it "returns nil matching any object" do
+      o = Object.new
+
+      suppress_warning do
+        (o =~ /Object/).should   be_nil
+        (o =~ 'Object').should   be_nil
+        (o =~ Object).should     be_nil
+        (o =~ Object.new).should be_nil
+        (o =~ nil).should        be_nil
+        (o =~ false).should      be_nil
+        (o =~ true).should       be_nil
+      end
+    end
+  end
+end
diff --git a/spec/ruby/core/numeric/step_spec.rb b/spec/ruby/core/numeric/step_spec.rb
index 1eb91aa1e5..96439927a4 100644
--- a/spec/ruby/core/numeric/step_spec.rb
+++ b/spec/ruby/core/numeric/step_spec.rb
@@ -61,6 +61,20 @@ describe "Numeric#step" do
             end
           end
         end
+
+        describe "type" do
+          ruby_version_is ""..."2.6" do
+            it "returns an instance of Enumerator" do
+              1.step(10).class.should == Enumerator
+            end
+          end
+
+          ruby_version_is "2.6" do
+            it "returns an instance of Enumerator::ArithmeticSequence" do
+              1.step(10).class.should == Enumerator::ArithmeticSequence
+            end
+          end
+        end
       end
     end
 
diff --git a/spec/ruby/core/proc/compose_spec.rb b/spec/ruby/core/proc/compose_spec.rb
new file mode 100644
index 0000000000..f1befe658b
--- /dev/null
+++ b/spec/ruby/core/proc/compose_spec.rb
@@ -0,0 +1,94 @@
+require_relative '../../spec_helper'
+require_relative 'shared/compose'
+
+ruby_version_is "2.6" do
+  describe "Proc#<<" do
+    it "returns a Proc that is the composition of self and the passed Proc" do
+      upcase = proc { |s| s.upcase }
+      succ = proc { |s| s.succ }
+
+      (succ << upcase).call('Ruby').should == "RUBZ"
+    end
+
+    it "calls passed Proc with arguments and then calls self with result" do
+      f = proc { |x| x * x }
+      g = proc { |x| x + x }
+
+      (f << g).call(2).should == 16
+      (g << f).call(2).should == 8
+    end
+
+    it "accepts any callable object" do
+      inc = proc { |n| n + 1 }
+
+      double = Object.new
+      def double.call(n); n * 2; end
+
+      (inc << double).call(3).should == 7
+    end
+
+    it_behaves_like :proc_compose, :<<, -> { proc { |s| s.upcase } }
+
+    describe "composition" do
+      it "is a Proc" do
+        f = proc { |x| x * x }
+        g = proc { |x| x + x }
+
+        (f << g).is_a?(Proc).should == true
+        (f << g).lambda?.should == false
+      end
+
+      it "may accept multiple arguments" do
+        inc = proc { |n| n + 1 }
+        mul = proc { |n, m| n * m }
+
+        (inc << mul).call(2, 3).should == 7
+      end
+    end
+  end
+
+  describe "Proc#>>" do
+    it "returns a Proc that is the composition of self and the passed Proc" do
+      upcase = proc { |s| s.upcase }
+      succ = proc { |s| s.succ }
+
+      (succ >> upcase).call('Ruby').should == "RUBZ"
+    end
+
+    it "calls passed Proc with arguments and then calls self with result" do
+      f = proc { |x| x * x }
+      g = proc { |x| x + x }
+
+      (f >> g).call(2).should == 8
+      (g >> f).call(2).should == 16
+    end
+
+    it "accepts any callable object" do
+      inc = proc { |n| n + 1 }
+
+      double = Object.new
+      def double.call(n); n * 2; end
+
+      (inc >> double).call(3).should == 8
+    end
+
+    it_behaves_like :proc_compose, :>>, -> { proc { |s| s.upcase } }
+
+    describe "composition" do
+      it "is a Proc" do
+        f = proc { |x| x * x }
+        g = proc { |x| x + x }
+
+        (f >> g).is_a?(Proc).should == true
+        (f >> g).lambda?.should == false
+      end
+
+      it "may accept multiple arguments" do
+        inc = proc { |n| n + 1 }
+        mul = proc { |n, m| n * m }
+
+        (mul >> inc).call(2, 3).should == 7
+      end
+    end
+  end
+end
diff --git a/spec/ruby/core/proc/shared/compose.rb b/spec/ruby/core/proc/shared/compose.rb
new file mode 100644
index 0000000000..64338cada8
--- /dev/null
+++ b/spec/ruby/core/proc/shared/compose.rb
@@ -0,0 +1,47 @@
+describe :proc_compose, shared: true do
+  ruby_version_is "2.6"..."2.7" do
+    it "raises NoMethodError when called if passed not callable object" do
+      not_callable = Object.new
+      composed = @object.call.send(@method, not_callable)
+
+      -> {
+        composed.call('a')
+      }.should raise_error(NoMethodError, /undefined method `call' for/)
+
+    end
+
+    it "when called does not try to coerce argument with #to_proc" do
+      succ = Object.new
+      def succ.to_proc(s); s.succ; end
+
+      composed = @object.call.send(@method, succ)
+
+      -> {
+        composed.call('a')
+      }.should raise_error(NoMethodError, /undefined method `call' for/)
+    end
+  end
+
+  ruby_version_is "2.7" do # https://bugs.ruby-lang.org/issues/15428
+    it "raises TypeError if passed not callable object" do
+      lhs = @object.call
+      not_callable = Object.new
+
+      -> {
+        lhs.send(@method, not_callable)
+      }.should raise_error(TypeError, "callable object is expected")
+
+    end
+
+    it "does not try to coerce argument with #to_proc" do
+      lhs = @object.call
+
+      succ = Object.new
+      def succ.to_proc(s); s.succ; end
+
+      -> {
+        lhs.send(@method, succ)
+      }.should raise_error(TypeError, "callable object is expected")
+    end
+  end
+end
diff --git a/spec/ruby/core/process/fixtures/in.txt b/spec/ruby/core/process/fixtures/in.txt
new file mode 100644
index 0000000000..cf52303bdc
--- /dev/null
+++ b/spec/ruby/core/process/fixtures/in.txt
@@ -0,0 +1 @@
+stdin
diff --git a/spec/ruby/core/process/spawn_spec.rb b/spec/ruby/core/process/spawn_spec.rb
index 951941888b..bb55fe299b 100644
--- a/spec/ruby/core/process/spawn_spec.rb
+++ b/spec/ruby/core/process/spawn_spec.rb
@@ -8,10 +8,10 @@ end
 
 describe :process_spawn_does_not_close_std_streams, shared: true do
   it "does not close STDIN" do
-    code = "STDOUT.puts STDIN.read(0).inspect"
+    code = "puts STDIN.read"
     cmd = "Process.wait Process.spawn(#{ruby_cmd(code).inspect}, #{@options.inspect})"
-    ruby_exe(cmd, args: "> #{@name}")
-    File.binread(@name).should == %[""#{newline}]
+    ruby_exe(cmd, args: "< #{fixture(__FILE__, "in.txt")} > #{@name}")
+    File.binread(@name).should == %[stdin#{newline}]
   end
 
   it "does not close STDOUT" do
@@ -530,7 +530,35 @@ describe "Process.spawn" do
     File.read(@name).should == "glarkbang"
   end
 
+  # :close_others
+
   platform_is_not :windows do
+    context "defaults :close_others to" do
+      ruby_version_is ""..."2.6" do
+        it "true" do
+          IO.pipe do |r, w|
+            w.close_on_exec = false
+            code = "begin; IO.new(#{w.fileno}).close; rescue Errno::EBADF; puts 'not inherited'; end"
+            Process.wait Process.spawn(ruby_cmd(code), :out => @name)
+            File.read(@name).should == "not inherited\n"
+          end
+        end
+      end
+
+      ruby_version_is "2.6" do
+        it "false" do
+          IO.pipe do |r, w|
+            w.close_on_exec = false
+            code = "io = IO.new(#{w.fileno}); io.puts('inherited'); io.close"
+            pid = Process.spawn(ruby_cmd(code))
+            w.close
+            Process.wait(pid)
+            r.read.should == "inherited\n"
+          end
+        end
+      end
+    end
+
     context "when passed close_others: true" do
       before :each do
         @options = { close_others: true }
diff --git a/spec/ruby/core/range/case_compare_spec.rb b/spec/ruby/core/range/case_compare_spec.rb
index 9a33c5b73b..37d8cc4677 100644
--- a/spec/ruby/core/range/case_compare_spec.rb
+++ b/spec/ruby/core/range/case_compare_spec.rb
@@ -9,12 +9,20 @@ describe "Range#===" do
       range.should_receive(:include?).with(2).and_return(:true)
       (range === 2).should == :true
     end
+
+    it "requires #succ method to be implemented" do
+      range = RangeSpecs::WithoutSucc.new(0)..RangeSpecs::WithoutSucc.new(10)
+
+      lambda do
+        range === RangeSpecs::WithoutSucc.new(2)
+      end.should raise_error(TypeError, /can't iterate from/)
+    end
   end
 
   ruby_version_is "2.6" do
     it "returns the result of calling #cover? on self" do
-      range = RangeSpecs::Custom.new(0)..RangeSpecs::Custom.new(10)
-      (range === RangeSpecs::Custom.new(2)).should == true
+      range = RangeSpecs::WithoutSucc.new(0)..RangeSpecs::WithoutSucc.new(10)
+      (range === RangeSpecs::WithoutSucc.new(2)).should == true
     end
   end
 end
diff --git a/spec/ruby/core/range/fixtures/classes.rb b/spec/ruby/core/range/fixtures/classes.rb
index b62704ca39..3a1df010b2 100644
--- a/spec/ruby/core/range/fixtures/classes.rb
+++ b/spec/ruby/core/range/fixtures/classes.rb
@@ -40,6 +40,28 @@ module RangeSpecs
     end
   end
 
+  class WithoutSucc
+    include Comparable
+    attr_reader :n
+
+    def initialize(n)
+      @n = n
+    end
+
+    def eql?(other)
+      inspect.eql? other.inspect
+    end
+    alias :== :eql?
+
+    def inspect
+      "WithoutSucc(#{@n})"
+    end
+
+    def <=>(other)
+      @n <=> other.n
+    end
+  end
+
   class Xs < Custom # represent a string of 'x's
     def succ
       Xs.new(@length + 1)
diff --git a/spec/ruby/core/range/new_spec.rb b/spec/ruby/core/range/new_spec.rb
index 26ea12867d..c110687163 100644
--- a/spec/ruby/core/range/new_spec.rb
+++ b/spec/ruby/core/range/new_spec.rb
@@ -42,4 +42,30 @@ describe "Range.new" do
       -> { Range.new(a, b) }.should raise_error(RangeSpecs::ComparisonError)
     end
   end
+
+  describe "endless range" do
+    it "does not allow range without left boundary" do
+      -> { Range.new(nil, 1) }.should raise_error(ArgumentError, /bad value for range/)
+    end
+
+    ruby_version_is ""..."2.6" do
+      it "does not allow range without right boundary" do
+        -> { Range.new(1, nil) }.should raise_error(ArgumentError, /bad value for range/)
+      end
+    end
+
+    ruby_version_is "2.6" do
+      it "allows endless right boundary" do
+        range = Range.new(1, nil)
+        range.end.should == nil
+      end
+
+      it "distinguishes ranges with included and excluded right boundary" do
+        range_exclude = Range.new(1, nil, true)
+        range_include = Range.new(1, nil, false)
+
+        range_exclude.should_not == range_include
+      end
+    end
+  end
 end
diff --git a/spec/ruby/core/range/percent_spec.rb b/spec/ruby/core/range/percent_spec.rb
new file mode 100644
index 0000000000..41badd4f72
--- /dev/null
+++ b/spec/ruby/core/range/percent_spec.rb
@@ -0,0 +1,18 @@
+require_relative '../../spec_helper'
+
+ruby_version_is "2.6" do
+  describe "Range#%" do
+    it "works as a Range#step" do
+      aseq = (1..10) % 2
+      aseq.class.should == Enumerator::ArithmeticSequence
+      aseq.begin.should == 1
+      aseq.end.should == 10
+      aseq.step.should == 2
+      aseq.to_a.should == [1, 3, 5, 7, 9]
+    end
+
+    it "produces an arithmetic sequence with a percent sign in #inspect" do
+      ((1..10) % 2).inspect.should == "((1..10).%(2))"
+    end
+  end
+end
diff --git a/spec/ruby/core/range/shared/cover.rb b/spec/ruby/core/range/shared/cover.rb
index b2de86531d..7d2367d712 100644
--- a/spec/ruby/core/range/shared/cover.rb
+++ b/spec/ruby/core/range/shared/cover.rb
@@ -90,4 +90,64 @@ describe :range_cover, shared: true do
       end
     end
   end
+
+  ruby_version_is "2.6" do
+    context "range argument" do
+      it "accepts range argument" do
+        (0..10).send(@method, (3..7)).should be_true
+        (0..10).send(@method, (3..15)).should be_false
+        (0..10).send(@method, (-2..7)).should be_false
+
+        (1.1..7.9).send(@method, (2.5..6.5)).should be_true
+        (1.1..7.9).send(@method, (2.5..8.5)).should be_false
+        (1.1..7.9).send(@method, (0.5..6.5)).should be_false
+
+        ('c'..'i').send(@method, ('d'..'f')).should be_true
+        ('c'..'i').send(@method, ('d'..'z')).should be_false
+        ('c'..'i').send(@method, ('a'..'f')).should be_false
+
+        range_10_100 = RangeSpecs::TenfoldSucc.new(10)..RangeSpecs::TenfoldSucc.new(100)
+        range_20_90 = RangeSpecs::TenfoldSucc.new(20)..RangeSpecs::TenfoldSucc.new(90)
+        range_20_110 = RangeSpecs::TenfoldSucc.new(20)..RangeSpecs::TenfoldSucc.new(110)
+        range_0_90 = RangeSpecs::TenfoldSucc.new(0)..RangeSpecs::TenfoldSucc.new(90)
+
+        range_10_100.send(@method, range_20_90).should be_true
+        range_10_100.send(@method, range_20_110).should be_false
+        range_10_100.send(@method, range_0_90).should be_false
+      end
+
+      it "supports boundaries of different comparable types" do
+        (0..10).send(@method, (3.1..7.9)).should be_true
+        (0..10).send(@method, (3.1..15.9)).should be_false
+        (0..10).send(@method, (-2.1..7.9)).should be_false
+      end
+
+      it "returns false if types are not comparable" do
+        (0..10).send(@method, ('a'..'z')).should be_false
+        (0..10).send(@method, (RangeSpecs::TenfoldSucc.new(0)..RangeSpecs::TenfoldSucc.new(100))).should be_false
+      end
+
+      it "honors exclusion of right boundary (:exclude_end option)" do
+        # Integer
+        (0..10).send(@method, (0..10)).should be_true
+        (0...10).send(@method, (0...10)).should be_true
+
+        (0..10).send(@method, (0...10)).should be_true
+        (0...10).send(@method, (0..10)).should be_false
+
+        (0...11).send(@method, (0..10)).should be_true
+        (0..10).send(@method, (0...11)).should be_true
+
+        # Float
+        (0..10.1).send(@method, (0..10.1)).should be_true
+        (0...10.1).send(@method, (0...10.1)).should be_true
+
+        (0..10.1).send(@method, (0...10.1)).should be_true
+        (0...10.1).send(@method, (0..10.1)).should be_false
+
+        (0...11.1).send(@method, (0..10.1)).should be_true
+        (0..10.1).send(@method, (0...11.1)).should be_false
+      end
+    end
+  end
 end
diff --git a/spec/ruby/core/range/step_spec.rb b/spec/ruby/core/range/step_spec.rb
index cdf66e4565..818207974a 100644
--- a/spec/ruby/core/range/step_spec.rb
+++ b/spec/ruby/core/range/step_spec.rb
@@ -1,21 +1,10 @@
 require_relative '../../spec_helper'
 
 describe "Range#step" do
-  step_enum_class = Enumerator
-  ruby_version_is "2.6" do
-    step_enum_class = Enumerator::ArithmeticSequence
-  end
-
   before :each do
     ScratchPad.record []
   end
 
-  it "returns an #{step_enum_class} when no block is given" do
-    enum = (1..10).step(4)
-    enum.should be_an_instance_of(step_enum_class)
-    enum.to_a.should eql([1, 5, 9])
-  end
-
   it "returns self" do
     r = 1..2
     r.step { }.should equal(r)
@@ -268,7 +257,7 @@ describe "Range#step" do
   end
 
   describe "when no block is given" do
-    describe "returned #{step_enum_class}" do
+    describe "returned Enumerator" do
       describe "size" do
         it "raises a TypeError if step does not respond to #to_int" do
           obj = mock("Range#step non-integer")
@@ -363,6 +352,28 @@ describe "Range#step" do
           enum.size.should == nil
         end
       end
+
+      describe "type" do
+        ruby_version_is ""..."2.6" do
+          it "returns an instance of Enumerator" do
+            (1..10).step.class.should == Enumerator
+          end
+        end
+
+        ruby_version_is "2.6" do
+          context "when both begin and end are numerics" do
+            it "returns an instance of Enumerator::ArithmeticSequence" do
+              (1..10).step.class.should == Enumerator::ArithmeticSequence
+            end
+          end
+
+          context "when begin and end are not numerics" do
+            it "returns an instance of Enumerator" do
+              ("a".."z").step.class.should == Enumerator
+            end
+          end
+        end
+      end
     end
   end
 end
diff --git a/spec/ruby/core/string/split_spec.rb b/spec/ruby/core/string/split_spec.rb
index b89a28c149..b451921c66 100644
--- a/spec/ruby/core/string/split_spec.rb
+++ b/spec/ruby/core/string/split_spec.rb
@@ -411,5 +411,17 @@ describe "String#split with Regexp" do
       returned_object.should == "chunky bacon"
       a.should == ["Chunky", "Bacon"]
     end
+
+    describe "for a String subclass" do
+      a = []
+      StringSpecs::MyString.new("a|b").split("|") { |str| a << str }
+      first, last = a
+
+      first.should be_an_instance_of(StringSpecs::MyString)
+      first.should == "a"
+
+      last.should be_an_instance_of(StringSpecs::MyString)
+      last.should == "b"
+    end
   end
 end
diff --git a/spec/ruby/core/struct/to_h_spec.rb b/spec/ruby/core/struct/to_h_spec.rb
index ddfbfbca61..b5f4e40701 100644
--- a/spec/ruby/core/struct/to_h_spec.rb
+++ b/spec/ruby/core/struct/to_h_spec.rb
@@ -14,10 +14,45 @@ describe "Struct#to_h" do
   end
 
   ruby_version_is "2.6" do
-    it "converts [key, value] pairs returned by the block to a hash" do
-      car = StructClasses::Car.new('Ford', 'Ranger')
-      h = car.to_h {|k, v| [k.to_s, "#{v}".downcase]}
-      h.should == {"make" => "ford", "model" => "ranger", "year" => ""}
+    context "with block" do
+      it "converts [key, value] pairs returned by the block to a hash" do
+        car = StructClasses::Car.new('Ford', 'Ranger')
+
+        h = car.to_h { |k, v| [k.to_s, "#{v}".downcase] }
+        h.should == { "make" => "ford", "model" => "ranger", "year" => "" }
+      end
+
+      it "raises ArgumentError if block returns longer or shorter array" do
+        -> do
+          StructClasses::Car.new.to_h { |k, v| [k.to_s, "#{v}".downcase, 1] }
+        end.should raise_error(ArgumentError, /element has wrong array length/)
+
+        -> do
+          StructClasses::Car.new.to_h { |k, v| [k] }
+        end.should raise_error(ArgumentError, /element has wrong array length/)
+      end
+
+      it "raises TypeError if block returns something other than Array" do
+        -> do
+          StructClasses::Car.new.to_h { |k, v| "not-array" }
+        end.should raise_error(TypeError, /wrong element type String/)
+      end
+
+      it "coerces returned pair to Array with #to_ary" do
+        x = mock('x')
+        x.stub!(:to_ary).and_return([:b, 'b'])
+
+        StructClasses::Car.new.to_h { |k| x }.should == { :b => 'b' }
+      end
+
+      it "does not coerce returned pair to Array with #to_a" do
+        x = mock('x')
+        x.stub!(:to_a).and_return([:b, 'b'])
+
+        -> do
+          StructClasses::Car.new.to_h { |k| x }
+        end.should raise_error(TypeError, /wrong element type MockObject/)
+      end
     end
   end
 end
diff --git a/spec/ruby/core/tracepoint/eval_script_spec.rb b/spec/ruby/core/tracepoint/eval_script_spec.rb
new file mode 100644
index 0000000000..8a153156d1
--- /dev/null
+++ b/spec/ruby/core/tracepoint/eval_script_spec.rb
@@ -0,0 +1,22 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+ruby_version_is "2.6" do
+  describe "#eval_script" do
+    ScratchPad.record []
+
+    script = <<-CODE
+      def foo
+        p :hello
+      end
+    CODE
+
+    TracePoint.new(:script_compiled) do |e|
+      ScratchPad << e.eval_script
+    end.enable do
+      eval script
+    end
+
+    ScratchPad.recorded.should == [script]
+  end
+end
diff --git a/spec/ruby/core/tracepoint/instruction_sequence_spec.rb b/spec/ruby/core/tracepoint/instruction_sequence_spec.rb
new file mode 100644
index 0000000000..50a9cd5722
--- /dev/null
+++ b/spec/ruby/core/tracepoint/instruction_sequence_spec.rb
@@ -0,0 +1,23 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+ruby_version_is "2.6" do
+  describe "#instruction_sequence" do
+    ScratchPad.record []
+
+    script = <<-CODE
+      def foo
+        p :hello
+      end
+    CODE
+
+    TracePoint.new(:script_compiled) do |e|
+      ScratchPad << e.instruction_sequence
+    end.enable do
+      eval script
+    end
+
+    ScratchPad.recorded.size.should == 1
+    ScratchPad.recorded[0].class.should == RubyVM::InstructionSequence
+  end
+end
-- 
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