[mocha-developer] I'm misunderstanding how stubs works

[Paul Butcher]

We're still just starting out with Mocha/Stubba, so please forgive any
newbie errors.

I'm using "stubs" to test some realtime functions, to control exactly which
time is returned from Time.now. I would expect the following test to pass:

  def test_two_stubs
    t = Time.now - 60
    Time.stubs(:now).returns(t)

    start_time = Time.now

    t += 20
    Time.stubs(:now).returns(t)

    end_time = Time.now

    assert_equal end_time - start_time, 20
  end

But it fails with:

  1) Failure:
test_two_stubs(MochaTest) [mochatest.rb:19]:
<0.0> expected but was
<20>.

I can create a test which works as I intend:

  def test_lambda
    t = Time.now - 60
    Time.stubs(:now).returns(lambda { t })

    start_time = Time.now

    t += 20

    end_time = Time.now

    assert_equal end_time - start_time, 20
  end

But I'd be interested to understand why the first version doesn't.

Thanks in advance for any help you can offer!

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Paul Butcher
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