MyString = Class.new(String)

MyString.define_singleton_method(:alphabet, lambda { 'abc' })

MyString.send(:define_method, :exclaim, lambda { |count = 1| "#{self}#{exclamation_mark count}" })

MyString.send(:define_method, :exclamation_mark, lambda { |count| '!' * count })

MyString.send(:alias_method, :!, :exclaim)

MyString.send(:private, :exclamation_mark)


require 'rspec/autorun'
 
describe MyString do
  describe '.alphabet' do
    specify { MyString.alphabet.should == 'abc' }
  end
 
  describe '#exclaim' do
    subject { MyString.new('james') }
 
    specify { subject.exclaim.should == 'james!' }
    specify { subject.exclaim(4).should == 'james!!!!' }
  end
 
  describe '#!' do
    subject { MyString.new('james') }
 
    specify { subject.!.should == 'james!' }
 
    it 'should be the same even if #exclaim is redefined' do
      MyString.class_eval { define_method(:exclaim) { '' } }
 
      subject.!.should == 'james!'
    end
  end
 
  describe '#exclamation_mark' do
    specify { subject.should_not respond_to(:exclamation_mark) }
  end
end