18 files changed, 200 insertions, 0 deletions
diff --git a/spec/ruby/core/nil/and_spec.rb b/spec/ruby/core/nil/and_spec.rb
new file mode 100644
index 0000000000..cd25aff1de
--- /dev/null
+++ b/spec/ruby/core/nil/and_spec.rb
@@ -0,0 +1,11 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#&" do
+  it "returns false" do
+    (nil & nil).should == false
+    (nil & true).should == false
+    (nil & false).should == false
+    (nil & "").should == false
+    (nil & mock('x')).should == false
+  end
+end
diff --git a/spec/ruby/core/nil/case_compare_spec.rb b/spec/ruby/core/nil/case_compare_spec.rb
new file mode 100644
index 0000000000..142560c6f5
--- /dev/null
+++ b/spec/ruby/core/nil/case_compare_spec.rb
@@ -0,0 +1,13 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#===" do
+  it "returns true for nil" do
+    (nil === nil).should == true
+  end
+
+  it "returns false for non-nil object" do
+    (nil === 1).should == false
+    (nil === "").should == false
+    (nil === Object).should == false
+  end
+end
diff --git a/spec/ruby/core/nil/dup_spec.rb b/spec/ruby/core/nil/dup_spec.rb
new file mode 100644
index 0000000000..0324b3f1f4
--- /dev/null
+++ b/spec/ruby/core/nil/dup_spec.rb
@@ -0,0 +1,7 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#dup" do
+  it "returns self" do
+    nil.dup.should equal(nil)
+  end
+end
diff --git a/spec/ruby/core/nil/inspect_spec.rb b/spec/ruby/core/nil/inspect_spec.rb
new file mode 100644
index 0000000000..1babc3d062
--- /dev/null
+++ b/spec/ruby/core/nil/inspect_spec.rb
@@ -0,0 +1,7 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#inspect" do
+  it "returns the string 'nil'" do
+    nil.inspect.should == "nil"
+  end
+end
diff --git a/spec/ruby/core/nil/match_spec.rb b/spec/ruby/core/nil/match_spec.rb
new file mode 100644
index 0000000000..bc1c591793
--- /dev/null
+++ b/spec/ruby/core/nil/match_spec.rb
@@ -0,0 +1,21 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#=~" do
+  it "returns nil matching any object" do
+    o = nil
+
+    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
+
+  it "should not warn" do
+    -> { nil =~ /a/ }.should_not complain(verbose: true)
+  end
+end
diff --git a/spec/ruby/core/nil/nil_spec.rb b/spec/ruby/core/nil/nil_spec.rb
new file mode 100644
index 0000000000..2cf97621c6
--- /dev/null
+++ b/spec/ruby/core/nil/nil_spec.rb
@@ -0,0 +1,7 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#nil?" do
+  it "returns true" do
+    nil.should.nil?
+  end
+end
diff --git a/spec/ruby/core/nil/nilclass_spec.rb b/spec/ruby/core/nil/nilclass_spec.rb
new file mode 100644
index 0000000000..7f6d8af25d
--- /dev/null
+++ b/spec/ruby/core/nil/nilclass_spec.rb
@@ -0,0 +1,15 @@
+require_relative '../../spec_helper'
+
+describe "NilClass" do
+  it ".allocate raises a TypeError" do
+    -> do
+      NilClass.allocate
+    end.should raise_error(TypeError)
+  end
+
+  it ".new is undefined" do
+    -> do
+      NilClass.new
+    end.should raise_error(NoMethodError)
+  end
+end
diff --git a/spec/ruby/core/nil/or_spec.rb b/spec/ruby/core/nil/or_spec.rb
new file mode 100644
index 0000000000..473a833d71
--- /dev/null
+++ b/spec/ruby/core/nil/or_spec.rb
@@ -0,0 +1,11 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#|" do
+  it "returns false if other is nil or false, otherwise true" do
+    (nil | nil).should == false
+    (nil | true).should == true
+    (nil | false).should == false
+    (nil | "").should == true
+    (nil | mock('x')).should == true
+  end
+end
diff --git a/spec/ruby/core/nil/rationalize_spec.rb b/spec/ruby/core/nil/rationalize_spec.rb
new file mode 100644
index 0000000000..84d6e6f056
--- /dev/null
+++ b/spec/ruby/core/nil/rationalize_spec.rb
@@ -0,0 +1,16 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#rationalize" do
+  it "returns 0/1" do
+    nil.rationalize.should == Rational(0, 1)
+  end
+
+  it "ignores a single argument" do
+    nil.rationalize(0.1).should == Rational(0, 1)
+  end
+
+  it "raises ArgumentError when passed more than one argument" do
+    -> { nil.rationalize(0.1, 0.1) }.should raise_error(ArgumentError)
+    -> { nil.rationalize(0.1, 0.1, 2) }.should raise_error(ArgumentError)
+  end
+end
diff --git a/spec/ruby/core/nil/singleton_method_spec.rb b/spec/ruby/core/nil/singleton_method_spec.rb
new file mode 100644
index 0000000000..8d898b1cc9
--- /dev/null
+++ b/spec/ruby/core/nil/singleton_method_spec.rb
@@ -0,0 +1,15 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#singleton_method" do
+  ruby_version_is '3.3' do
+    it "raises regardless of whether NilClass defines the method" do
+      -> { nil.singleton_method(:foo) }.should raise_error(NameError)
+      begin
+        def (nil).foo; end
+        -> { nil.singleton_method(:foo) }.should raise_error(NameError)
+      ensure
+        NilClass.send(:remove_method, :foo)
+      end
+    end
+  end
+end
diff --git a/spec/ruby/core/nil/to_a_spec.rb b/spec/ruby/core/nil/to_a_spec.rb
new file mode 100644
index 0000000000..b8b339e330
--- /dev/null
+++ b/spec/ruby/core/nil/to_a_spec.rb
@@ -0,0 +1,7 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#to_a" do
+  it "returns an empty array" do
+    nil.to_a.should == []
+  end
+end
diff --git a/spec/ruby/core/nil/to_c_spec.rb b/spec/ruby/core/nil/to_c_spec.rb
new file mode 100644
index 0000000000..e0052be5bd
--- /dev/null
+++ b/spec/ruby/core/nil/to_c_spec.rb
@@ -0,0 +1,7 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#to_c" do
+  it "returns Complex(0, 0)" do
+    nil.to_c.should eql(Complex(0, 0))
+  end
+end
diff --git a/spec/ruby/core/nil/to_f_spec.rb b/spec/ruby/core/nil/to_f_spec.rb
new file mode 100644
index 0000000000..a5f24ba3bf
--- /dev/null
+++ b/spec/ruby/core/nil/to_f_spec.rb
@@ -0,0 +1,11 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#to_f" do
+  it "returns 0.0" do
+    nil.to_f.should == 0.0
+  end
+
+  it "does not cause NilClass to be coerced to Float" do
+    (0.0 == nil).should == false
+  end
+end
diff --git a/spec/ruby/core/nil/to_h_spec.rb b/spec/ruby/core/nil/to_h_spec.rb
new file mode 100644
index 0000000000..5c8d5dc25a
--- /dev/null
+++ b/spec/ruby/core/nil/to_h_spec.rb
@@ -0,0 +1,8 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#to_h" do
+  it "returns an empty hash" do
+    nil.to_h.should == {}
+    nil.to_h.default.should == nil
+  end
+end
diff --git a/spec/ruby/core/nil/to_i_spec.rb b/spec/ruby/core/nil/to_i_spec.rb
new file mode 100644
index 0000000000..d3d088e999
--- /dev/null
+++ b/spec/ruby/core/nil/to_i_spec.rb
@@ -0,0 +1,11 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#to_i" do
+  it "returns 0" do
+    nil.to_i.should == 0
+  end
+
+  it "does not cause NilClass to be coerced to Integer" do
+    (0 == nil).should == false
+  end
+end
diff --git a/spec/ruby/core/nil/to_r_spec.rb b/spec/ruby/core/nil/to_r_spec.rb
new file mode 100644
index 0000000000..8be43baf00
--- /dev/null
+++ b/spec/ruby/core/nil/to_r_spec.rb
@@ -0,0 +1,7 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#to_r" do
+  it "returns 0/1" do
+    nil.to_r.should == Rational(0, 1)
+  end
+end
diff --git a/spec/ruby/core/nil/to_s_spec.rb b/spec/ruby/core/nil/to_s_spec.rb
new file mode 100644
index 0000000000..fa0b929677
--- /dev/null
+++ b/spec/ruby/core/nil/to_s_spec.rb
@@ -0,0 +1,15 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#to_s" do
+  it "returns the string ''" do
+    nil.to_s.should == ""
+  end
+
+  it "returns a frozen string" do
+    nil.to_s.should.frozen?
+  end
+
+  it "always returns the same string" do
+    nil.to_s.should equal(nil.to_s)
+  end
+end
diff --git a/spec/ruby/core/nil/xor_spec.rb b/spec/ruby/core/nil/xor_spec.rb
new file mode 100644
index 0000000000..b45da9d443
--- /dev/null
+++ b/spec/ruby/core/nil/xor_spec.rb
@@ -0,0 +1,11 @@
+require_relative '../../spec_helper'
+
+describe "NilClass#^" do
+  it "returns false if other is nil or false, otherwise true" do
+    (nil ^ nil).should == false
+    (nil ^ true).should == true
+    (nil ^ false).should == false
+    (nil ^ "").should == true
+    (nil ^ mock('x')).should == true
+  end
+end