Method test_default_factory

Lib/test/test_dataclasses/__init__.py:1363–1418

(self)

        self.assertEqual(c.shadowed, 30)

    def test_default_factory(self):
        # Test a factory that returns a new list.
        @dataclass
        class C:
            x: int
            y: list = field(default_factory=list)

        c0 = C(3)
        c1 = C(3)
        self.assertEqual(c0.x, 3)
        self.assertEqual(c0.y, [])
        self.assertEqual(c0, c1)
        self.assertIsNot(c0.y, c1.y)
        self.assertEqual(astuple(C(5, [1])), (5, [1]))

        # Test a factory that returns a shared list.
        l = []
        @dataclass
        class C:
            x: int
            y: list = field(default_factory=lambda: l)

        c0 = C(3)
        c1 = C(3)
        self.assertEqual(c0.x, 3)
        self.assertEqual(c0.y, [])
        self.assertEqual(c0, c1)
        self.assertIs(c0.y, c1.y)
        self.assertEqual(astuple(C(5, [1])), (5, [1]))

        # Test various other field flags.
        # repr
        @dataclass
        class C:
            x: list = field(default_factory=list, repr=False)
        self.assertEqual(repr(C()), 'TestCase.test_default_factory.<locals>.C()')
        self.assertEqual(C().x, [])

        # hash
        @dataclass(unsafe_hash=True)
        class C:
            x: list = field(default_factory=list, hash=False)
        self.assertEqual(astuple(C()), ([],))
        self.assertEqual(hash(C()), hash(()))

        # init (see also test_default_factory_with_no_init)
        @dataclass
        class C:
            x: list = field(default_factory=list, init=False)
        self.assertEqual(astuple(C()), ([],))

        # compare
        @dataclass
        class C:
            x: list = field(default_factory=list, compare=False)
        self.assertEqual(C(), C([1]))

    def test_default_factory_with_no_init(self):