title: Constructor injection and PyMock
body: <p>How to correctly record mock for this example (and simplified) scenario?</p>
  
  <pre><code>class First:
      def register(self, handler):
          pass
  
  class Second:
      def __init__(self, first):
          self.__first = first
          self.__first.register(self)
  </code></pre>
  
  <p>Now I have a test:</p>
  
  <pre><code>class SecondTest(PyMockTestCase):
      def test_registration(self):
          first = self.mock();
          first.register(?????) # what to pass as argument?
          self.replay()
          sut = Second(first)
          self.verify()
  </code></pre>