Feeding mock objects DI style

rspec_DI_intro.rb

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my_world.rb

class MyWorld

  def initialize
    @king = King.new
  end

  def king_of_the_world
    @king.name
  end
end

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my_world_spec.rb

describe MyWorld

  class TestKing
    def name
      "foobar"
    end
  end

  before(:each) do
    @test_king = TestKing.new
    King.stub!(:new).and_return(@test_king)

    @world = MyWorld.new
  end

  it "knows the king of the world"
    @world.king_of_the_world.should == "foobar"
  end
end