test_functools.py 文件源码

def test_cmp_to_key_arguments(self):
        def cmp1(x, y):
            return (x > y) - (x < y)
        key = functools.cmp_to_key(mycmp=cmp1)
        self.assertEqual(key(obj=3), key(obj=3))
        self.assertGreater(key(obj=3), key(obj=1))
        with self.assertRaises((TypeError, AttributeError)):
            key(3) > 1    # rhs is not a K object
        with self.assertRaises((TypeError, AttributeError)):
            1 < key(3)    # lhs is not a K object
        with self.assertRaises(TypeError):
            key = functools.cmp_to_key()             # too few args
        with self.assertRaises(TypeError):
            key = functools.cmp_to_key(cmp1, None)   # too many args
        key = functools.cmp_to_key(cmp1)
        with self.assertRaises(TypeError):
            key()                                    # too few args
        with self.assertRaises(TypeError):
            key(None, None)                          # too many args