Method test_hash_field_rules

Lib/test/test_dataclasses/__init__.py:610–634

(self)

                a: Any = unhashable

    def test_hash_field_rules(self):
        # Test all 6 cases of:
        #  hash=True/False/None
        #  compare=True/False
        for (hash_,    compare, result  ) in [
            (True,     False,   'field' ),
            (True,     True,    'field' ),
            (False,    False,   'absent'),
            (False,    True,    'absent'),
            (None,     False,   'absent'),
            (None,     True,    'field' ),
            ]:
            with self.subTest(hash=hash_, compare=compare):
                @dataclass(unsafe_hash=True)
                class C:
                    x: int = field(compare=compare, hash=hash_, default=5)

                if result == 'field':
                    # __hash__ contains the field.
                    self.assertEqual(hash(C(5)), hash((5,)))
                elif result == 'absent':
                    # The field is not present in the hash.
                    self.assertEqual(hash(C(5)), hash(()))
                else:
                    assert False, f'unknown result {result!r}'

    def test_init_false_no_default(self):
        # If init=False and no default value, then the field won't be