Method test_defaults

Lib/test/test_collections.py:349–397

(self)

        self.assertRaises(TypeError, Point._make, [11, 22, 33])             # catch too many args

    def test_defaults(self):
        Point = namedtuple('Point', 'x y', defaults=(10, 20))              # 2 defaults
        self.assertEqual(Point._field_defaults, {'x': 10, 'y': 20})
        self.assertEqual(Point(1, 2), (1, 2))
        self.assertEqual(Point(1), (1, 20))
        self.assertEqual(Point(), (10, 20))

        Point = namedtuple('Point', 'x y', defaults=(20,))                 # 1 default
        self.assertEqual(Point._field_defaults, {'y': 20})
        self.assertEqual(Point(1, 2), (1, 2))
        self.assertEqual(Point(1), (1, 20))

        Point = namedtuple('Point', 'x y', defaults=())                     # 0 defaults
        self.assertEqual(Point._field_defaults, {})
        self.assertEqual(Point(1, 2), (1, 2))
        with self.assertRaises(TypeError):
            Point(1)

        with self.assertRaises(TypeError):                                  # catch too few args
            Point()
        with self.assertRaises(TypeError):                                  # catch too many args
            Point(1, 2, 3)
        with self.assertRaises(TypeError):                                  # too many defaults
            Point = namedtuple('Point', 'x y', defaults=(10, 20, 30))
        with self.assertRaises(TypeError):                                  # non-iterable defaults
            Point = namedtuple('Point', 'x y', defaults=10)
        with self.assertRaises(TypeError):                                  # another non-iterable default
            Point = namedtuple('Point', 'x y', defaults=False)

        Point = namedtuple('Point', 'x y', defaults=None)                   # default is None
        self.assertEqual(Point._field_defaults, {})
        self.assertIsNone(Point.__new__.__defaults__, None)
        self.assertEqual(Point(10, 20), (10, 20))
        with self.assertRaises(TypeError):                                  # catch too few args
            Point(10)

        Point = namedtuple('Point', 'x y', defaults=[10, 20])               # allow non-tuple iterable
        self.assertEqual(Point._field_defaults, {'x': 10, 'y': 20})
        self.assertEqual(Point.__new__.__defaults__, (10, 20))
        self.assertEqual(Point(1, 2), (1, 2))
        self.assertEqual(Point(1), (1, 20))
        self.assertEqual(Point(), (10, 20))

        Point = namedtuple('Point', 'x y', defaults=iter([10, 20]))         # allow plain iterator
        self.assertEqual(Point._field_defaults, {'x': 10, 'y': 20})
        self.assertEqual(Point.__new__.__defaults__, (10, 20))
        self.assertEqual(Point(1, 2), (1, 2))
        self.assertEqual(Point(1), (1, 20))
        self.assertEqual(Point(), (10, 20))

    def test_readonly(self):
        Point = namedtuple('Point', 'x y')