def test_is_unhappy(self, sys_mock):
        """This is mocking the complete library. Try that in Java."""
        # setup
        foobar = Foobar()

        # exercise
        foobar._i_am_happy(False)

        # Verify
        self.assertEqual(1, sys_mock.exit.call_count)
    def test_is_happy(self):
        """This is testing a private method"""
        # setup
        foobar = Foobar()

        # exercise
        result = foobar._i_am_happy(True)

        # verify
        self.assertEqual("happy", result)