def test_pop_not_last(self):
        stack = OutputFormatterStyleStack()
        s1 = OutputFormatterStyle('white', 'black')
        s2 = OutputFormatterStyle('yellow', 'blue')
        s3 = OutputFormatterStyle('green', 'red')
        stack.push(s1)
        stack.push(s2)
        stack.push(s3)

        self.assertEqual(s2, stack.pop(s2))
        self.assertEqual(s1, stack.pop())
    def test_pop_not_last(self):
        stack = OutputFormatterStyleStack()
        s1 = OutputFormatterStyle('white', 'black')
        s2 = OutputFormatterStyle('yellow', 'blue')
        s3 = OutputFormatterStyle('green', 'red')
        stack.push(s1)
        stack.push(s2)
        stack.push(s3)

        self.assertEqual(s2, stack.pop(s2))
        self.assertEqual(s1, stack.pop())
    def test_pop_empty(self):
        stack = OutputFormatterStyleStack()

        self.assertTrue(isinstance(stack.pop(), OutputFormatterStyle))
    def test_pop_empty(self):
        stack = OutputFormatterStyleStack()

        self.assertTrue(isinstance(stack.pop(), OutputFormatterStyle))