Method test_dynamics

Lib/test/test_descr.py:1420–1485

(self)

        self.assertRaises(TypeError, MyABC.a.__set__, u, 3)

    def test_dynamics(self):
        # Testing class attribute propagation...
        class D(object):
            pass
        class E(D):
            pass
        class F(D):
            pass
        D.foo = 1
        self.assertEqual(D.foo, 1)
        # Test that dynamic attributes are inherited
        self.assertEqual(E.foo, 1)
        self.assertEqual(F.foo, 1)
        # Test dynamic instances
        class C(object):
            pass
        a = C()
        self.assertNotHasAttr(a, "foobar")
        C.foobar = 2
        self.assertEqual(a.foobar, 2)
        C.method = lambda self: 42
        self.assertEqual(a.method(), 42)
        C.__repr__ = lambda self: "C()"
        self.assertEqual(repr(a), "C()")
        C.__int__ = lambda self: 100
        self.assertEqual(int(a), 100)
        self.assertEqual(a.foobar, 2)
        self.assertNotHasAttr(a, "spam")
        def mygetattr(self, name):
            if name == "spam":
                return "spam"
            raise AttributeError
        C.__getattr__ = mygetattr
        self.assertEqual(a.spam, "spam")
        a.new = 12
        self.assertEqual(a.new, 12)
        def mysetattr(self, name, value):
            if name == "spam":
                raise AttributeError
            return object.__setattr__(self, name, value)
        C.__setattr__ = mysetattr
        with self.assertRaises(AttributeError):
            a.spam = "not spam"

        self.assertEqual(a.spam, "spam")
        class D(C):
            pass
        d = D()
        d.foo = 1
        self.assertEqual(d.foo, 1)

        # Test handling of int*seq and seq*int
        class I(int):
            pass
        self.assertEqual("a"*I(2), "aa")
        self.assertEqual(I(2)*"a", "aa")
        self.assertEqual(2*I(3), 6)
        self.assertEqual(I(3)*2, 6)