Quick and Dirty "Mock" and "Stub" functionality in ruby. Could be used for making Independent mock files or for NullObjects

StubbyMock.rb

require 'rubygems'
require 'rspec'

module FakeIt
  def self.included(base)
    base.extend(ClassMethods)
  end
  module ClassMethods
    def mocks(class_name)
      class_name.instance_methods(false).map { |method_name| define_method(method_name)  { |*args| } }
      class_name.methods(false).map { |method_name| define_singleton_method(method_name) { |*args| } }
    end
    def will_stub(method_name, &block)
      raise "Method Isn't Defined on Base Class" unless method_defined?(method_name)
      define_method(method_name) { |*args| yield }
    end
  end
end


# TEST CLASS
class MyNode
  def hello
    "hi"
  end
  def johnny
    "bill"
  end
  def add(first, second)
    first + second
  end
  def self.used
    "u called me"
  end
end

class MyFakeNode
  include FakeIt
  mocks MyNode
  will_stub(:add) { "five" }
end

mfn = MyFakeNode.new

MyFakeNode.used #=> "u called me"

mfn.hello    #=> nil (No error is thrown however)

mfn.add      #=> "five"
mfn.add 2, 3 #=> "five"

mfn.subtract #=> NoMethodError

describe FakeIt do
  it "mocks all methods on fake class" do
    MyFakeNode.instance_methods(false).should == MyNode.instance_methods(false)
  end
  it "mocks all class methods on fake class" do
    MyFakeNode.methods(false).should == MyNode.methods(false)
  end
  it "returns the stubbed response for a given methods" do
    a = MyFakeNode.new
    a.add.should == "five"
  end
  it "should raise exception if method is not defined on base class" do
    lambda {
      a = class MyFake
        include FakeIt
        mocks MyNode
        will_stub(:subtract) { "10"}
      end
    }.should raise_error
  end
end