Default collections namedtuple

default_namedtuple.py

from collections import namedtuple  # pylint: disable=import-self


def default_namedtuple(typename='Case', **defaults):
    NamedTuple = namedtuple(typename, defaults)  # pylint: disable=invalid-name
    default_tuple = NamedTuple(**defaults)
    customizable_tuple = default_tuple._replace
    return customizable_tuple

  
import unittest


class TestDefaultNamedTuple(unittest.TestCase):

    def test_default_typename(self):
        default = default_namedtuple(foo='a')
        custom = default()
        actual_typename = type(custom).__name__
        self.assertEqual(actual_typename, 'Case')

    def test_default_values(self):
        default = default_namedtuple('Foo', bar='a', baz=1)
        custom = default()
        actual_typename = type(custom).__name__
        self.assertEqual(actual_typename, 'Foo')
        self.assertEqual(custom.bar, 'a')
        self.assertEqual(custom.baz, 1)

    def test_custom_values(self):
        default = default_namedtuple('Foo', bar='a', baz=1, qux=False)
        custom = default(baz=2, qux=True)
        self.assertEqual(custom.bar, 'a')
        self.assertEqual(custom.baz, 2)
        self.assertTrue(custom.qux)

    def test_default_values_persistence(self):
        default = default_namedtuple(foo='a', bar=1)
        custom1 = default(foo='b', bar=2)
        custom2 = default(foo='c')
        self.assertEqual(custom1.foo, 'b')
        self.assertEqual(custom1.bar, 2)
        self.assertEqual(custom2.foo, 'c')
        self.assertEqual(custom2.bar, 1)