1 files changed, 48 insertions, 26 deletions
diff --git a/spec/ruby/core/module/undef_method_spec.rb b/spec/ruby/core/module/undef_method_spec.rb
index 54c3d37c7f..d77640cb7e 100644
--- a/spec/ruby/core/module/undef_method_spec.rb
+++ b/spec/ruby/core/module/undef_method_spec.rb
@@ -1,5 +1,5 @@
-require File.expand_path('../../../spec_helper', __FILE__)
-require File.expand_path('../fixtures/classes', __FILE__)
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
 
 module ModuleSpecs
   class Parent
@@ -18,15 +18,8 @@ describe "Module#undef_method" do
     @module = Module.new { def method_to_undef; end }
   end
 
-  ruby_version_is ''...'2.5' do
-    it "is a private method" do
-      Module.should have_private_instance_method(:undef_method, false)
-    end
-  end
-  ruby_version_is '2.5' do
-    it "is a public method" do
-      Module.should have_public_instance_method(:undef_method, false)
-    end
+  it "is a public method" do
+    Module.public_instance_methods(false).should.include?(:undef_method)
   end
 
   it "requires multiple arguments" do
@@ -41,8 +34,8 @@ describe "Module#undef_method" do
     x = klass.new
     klass.send(:undef_method, :method_to_undef, :another_method_to_undef)
 
-    lambda { x.method_to_undef }.should raise_error(NoMethodError)
-    lambda { x.another_method_to_undef }.should raise_error(NoMethodError)
+    -> { x.method_to_undef }.should.raise(NoMethodError)
+    -> { x.another_method_to_undef }.should.raise(NoMethodError)
   end
 
   it "does not undef any instance methods when argument not given" do
@@ -53,11 +46,40 @@ describe "Module#undef_method" do
   end
 
   it "returns self" do
-    @module.send(:undef_method, :method_to_undef).should equal(@module)
+    @module.send(:undef_method, :method_to_undef).should.equal?(@module)
+  end
+
+  it "raises a NameError when passed a missing name for a module" do
+    -> { @module.send :undef_method, :not_exist }.should.raise(NameError, /undefined method [`']not_exist' for module [`']#{@module}'/) { |e|
+      # a NameError and not a NoMethodError
+      e.class.should == NameError
+    }
+  end
+
+  it "raises a NameError when passed a missing name for a class" do
+    klass = Class.new
+    -> { klass.send :undef_method, :not_exist }.should.raise(NameError, /undefined method [`']not_exist' for class [`']#{klass}'/) { |e|
+      # a NameError and not a NoMethodError
+      e.class.should == NameError
+    }
+  end
+
+  it "raises a NameError when passed a missing name for a singleton class" do
+    klass = Class.new
+    obj = klass.new
+    sclass = obj.singleton_class
+
+    -> { sclass.send :undef_method, :not_exist }.should.raise(NameError, /undefined method [`']not_exist' for class [`']#{sclass}'/) { |e|
+      e.message.should =~ /[`']#<Class:#<#<Class:/
+
+      # a NameError and not a NoMethodError
+      e.class.should == NameError
+    }
   end
 
-  it "raises a NameError when passed a missing name" do
-    lambda { @module.send :undef_method, :not_exist }.should raise_error(NameError) { |e|
+  it "raises a NameError when passed a missing name for a metaclass" do
+    klass = String.singleton_class
+    -> { klass.send :undef_method, :not_exist }.should.raise(NameError, /undefined method [`']not_exist' for class [`']String'/) { |e|
       # a NameError and not a NoMethodError
       e.class.should == NameError
     }
@@ -68,20 +90,20 @@ describe "Module#undef_method" do
       @frozen = @module.dup.freeze
     end
 
-    it "raises a RuntimeError when passed a name" do
-      lambda { @frozen.send :undef_method, :method_to_undef }.should raise_error(RuntimeError)
+    it "raises a FrozenError when passed a name" do
+      -> { @frozen.send :undef_method, :method_to_undef }.should.raise(FrozenError)
     end
 
-    it "raises a RuntimeError when passed a missing name" do
-      lambda { @frozen.send :undef_method, :not_exist }.should raise_error(RuntimeError)
+    it "raises a FrozenError when passed a missing name" do
+      -> { @frozen.send :undef_method, :not_exist }.should.raise(FrozenError)
     end
 
     it "raises a TypeError when passed a not name" do
-      lambda { @frozen.send :undef_method, Object.new }.should raise_error(TypeError)
+      -> { @frozen.send :undef_method, Object.new }.should.raise(TypeError)
     end
 
     it "does not raise exceptions when no arguments given" do
-      @frozen.send(:undef_method).should equal(@frozen)
+      @frozen.send(:undef_method).should.equal?(@frozen)
     end
   end
 end
@@ -98,7 +120,7 @@ describe "Module#undef_method with symbol" do
 
     klass.send :undef_method, :method_to_undef
 
-    lambda { x.method_to_undef }.should raise_error(NoMethodError)
+    -> { x.method_to_undef }.should.raise(NoMethodError)
   end
 
   it "removes a method defined in a super class" do
@@ -108,7 +130,7 @@ describe "Module#undef_method with symbol" do
 
     child_class.send :undef_method, :method_to_undef
 
-    lambda { child.method_to_undef }.should raise_error(NoMethodError)
+    -> { child.method_to_undef }.should.raise(NoMethodError)
   end
 
   it "does not remove a method defined in a super class when removed from a subclass" do
@@ -134,7 +156,7 @@ describe "Module#undef_method with string" do
 
     klass.send :undef_method, 'another_method_to_undef'
 
-    lambda { x.another_method_to_undef }.should raise_error(NoMethodError)
+    -> { x.another_method_to_undef }.should.raise(NoMethodError)
   end
 
   it "removes a method defined in a super class" do
@@ -144,7 +166,7 @@ describe "Module#undef_method with string" do
 
     child_class.send :undef_method, 'another_method_to_undef'
 
-    lambda { child.another_method_to_undef }.should raise_error(NoMethodError)
+    -> { child.another_method_to_undef }.should.raise(NoMethodError)
   end
 
   it "does not remove a method defined in a super class when removed from a subclass" do