test_yesno.py

from django.template.defaultfilters import yesno
from django.test import SimpleTestCase


class FunctionTests(SimpleTestCase):

    def test_true(self):
        self.assertEqual(yesno(True), 'yes')

    def test_false(self):
        self.assertEqual(yesno(False), 'no')

    def test_none(self):
        self.assertEqual(yesno(None), 'maybe')

    def test_true_arguments(self):
        self.assertEqual(yesno(True, 'certainly,get out of town,perhaps'), 'certainly')

    def test_false_arguments(self):
        self.assertEqual(yesno(False, 'certainly,get out of town,perhaps'), 'get out of town')

    def test_none_two_arguments(self):
        self.assertEqual(yesno(None, 'certainly,get out of town'), 'get out of town')

    def test_none_three_arguments(self):
        self.assertEqual(yesno(None, 'certainly,get out of town,perhaps'), 'perhaps')

    def test_invalid_value(self):
        self.assertIs(yesno(True, 'yes'), True)
        self.assertIs(yesno(False, 'yes'), False)
        self.assertIsNone(yesno(None, 'yes'))