def test_signal(self):
        """
        Test the signal method.

        @raise AssertionError: If the test fails.
        """
        mediator = Mediator()
        mediator.connect('set_dog_sound', self.dog.set_sound)
        mediator.connect('set_cat_sound', self.cat.set_sound)
        mediator.signal('set_dog_sound', 'woof')
        mediator.signal('set_cat_sound', 'meow')

        self.assertEquals('woof', self.dog.sound)
        self.assertEquals('meow', self.cat.sound)

        Test the signal method.

        @raise AssertionError: If the test fails.
        
tests/behavioral_tests/test_mediator.py