1 files changed, 181 insertions, 0 deletions
diff --git a/spec/ruby/core/module/undef_method_spec.rb b/spec/ruby/core/module/undef_method_spec.rb
new file mode 100644
index 0000000000..d4efcd51cb
--- /dev/null
+++ b/spec/ruby/core/module/undef_method_spec.rb
@@ -0,0 +1,181 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/classes'
+
+module ModuleSpecs
+  class Parent
+    def method_to_undef() 1 end
+    def another_method_to_undef() 1 end
+  end
+
+  class Ancestor
+    def method_to_undef() 1 end
+    def another_method_to_undef() 1 end
+  end
+end
+
+describe "Module#undef_method" do
+  before :each do
+    @module = Module.new { def method_to_undef; end }
+  end
+
+  it "is a public method" do
+    Module.should have_public_instance_method(:undef_method, false)
+  end
+
+  it "requires multiple arguments" do
+    Module.instance_method(:undef_method).arity.should < 0
+  end
+
+  it "allows multiple methods to be removed at once" do
+    klass = Class.new do
+      def method_to_undef() 1 end
+      def another_method_to_undef() 1 end
+    end
+    x = klass.new
+    klass.send(:undef_method, :method_to_undef, :another_method_to_undef)
+
+    -> { x.method_to_undef }.should raise_error(NoMethodError)
+    -> { x.another_method_to_undef }.should raise_error(NoMethodError)
+  end
+
+  it "does not undef any instance methods when argument not given" do
+    before = @module.instance_methods(true) + @module.private_instance_methods(true)
+    @module.send :undef_method
+    after = @module.instance_methods(true) + @module.private_instance_methods(true)
+    before.sort.should == after.sort
+  end
+
+  it "returns self" do
+    @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_error(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_error(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_error(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 for a metaclass" do
+    klass = String.singleton_class
+    -> { klass.send :undef_method, :not_exist }.should raise_error(NameError, /undefined method [`']not_exist' for class [`']String'/) { |e|
+      # a NameError and not a NoMethodError
+      e.class.should == NameError
+    }
+  end
+
+  describe "on frozen instance" do
+    before :each do
+      @frozen = @module.dup.freeze
+    end
+
+    it "raises a FrozenError when passed a name" do
+      -> { @frozen.send :undef_method, :method_to_undef }.should raise_error(FrozenError)
+    end
+
+    it "raises a FrozenError when passed a missing name" do
+      -> { @frozen.send :undef_method, :not_exist }.should raise_error(FrozenError)
+    end
+
+    it "raises a TypeError when passed a not name" do
+      -> { @frozen.send :undef_method, Object.new }.should raise_error(TypeError)
+    end
+
+    it "does not raise exceptions when no arguments given" do
+      @frozen.send(:undef_method).should equal(@frozen)
+    end
+  end
+end
+
+describe "Module#undef_method with symbol" do
+  it "removes a method defined in a class" do
+    klass = Class.new do
+      def method_to_undef() 1 end
+      def another_method_to_undef() 1 end
+    end
+    x = klass.new
+
+    x.method_to_undef.should == 1
+
+    klass.send :undef_method, :method_to_undef
+
+    -> { x.method_to_undef }.should raise_error(NoMethodError)
+  end
+
+  it "removes a method defined in a super class" do
+    child_class = Class.new(ModuleSpecs::Parent)
+    child = child_class.new
+    child.method_to_undef.should == 1
+
+    child_class.send :undef_method, :method_to_undef
+
+    -> { child.method_to_undef }.should raise_error(NoMethodError)
+  end
+
+  it "does not remove a method defined in a super class when removed from a subclass" do
+    descendant = Class.new(ModuleSpecs::Ancestor)
+    ancestor = ModuleSpecs::Ancestor.new
+    ancestor.method_to_undef.should == 1
+
+    descendant.send :undef_method, :method_to_undef
+
+    ancestor.method_to_undef.should == 1
+  end
+end
+
+describe "Module#undef_method with string" do
+  it "removes a method defined in a class" do
+    klass = Class.new do
+      def method_to_undef() 1 end
+      def another_method_to_undef() 1 end
+    end
+    x = klass.new
+
+    x.another_method_to_undef.should == 1
+
+    klass.send :undef_method, 'another_method_to_undef'
+
+    -> { x.another_method_to_undef }.should raise_error(NoMethodError)
+  end
+
+  it "removes a method defined in a super class" do
+    child_class = Class.new(ModuleSpecs::Parent)
+    child = child_class.new
+    child.another_method_to_undef.should == 1
+
+    child_class.send :undef_method, 'another_method_to_undef'
+
+    -> { child.another_method_to_undef }.should raise_error(NoMethodError)
+  end
+
+  it "does not remove a method defined in a super class when removed from a subclass" do
+    descendant = Class.new(ModuleSpecs::Ancestor)
+    ancestor = ModuleSpecs::Ancestor.new
+    ancestor.another_method_to_undef.should == 1
+
+    descendant.send :undef_method, 'another_method_to_undef'
+
+    ancestor.another_method_to_undef.should == 1
+  end
+end