test_collections.py 文件源码

def test_MutableSequence_mixins(self):
        # Test the mixins of MutableSequence by creating a miminal concrete
        # class inherited from it.
        class MutableSequenceSubclass(MutableSequence):
            def __init__(self):
                self.lst = []

            def __setitem__(self, index, value):
                self.lst[index] = value

            def __getitem__(self, index):
                return self.lst[index]

            def __len__(self):
                return len(self.lst)

            def __delitem__(self, index):
                del self.lst[index]

            def insert(self, index, value):
                self.lst.insert(index, value)

        mss = MutableSequenceSubclass()
        mss.append(0)
        mss.extend((1, 2, 3, 4))
        self.assertEqual(len(mss), 5)
        self.assertEqual(mss[3], 3)
        mss.reverse()
        self.assertEqual(mss[3], 1)
        mss.pop()
        self.assertEqual(len(mss), 4)
        mss.remove(3)
        self.assertEqual(len(mss), 3)
        mss += (10, 20, 30)
        self.assertEqual(len(mss), 6)
        self.assertEqual(mss[-1], 30)
        mss.clear()
        self.assertEqual(len(mss), 0)

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