edan_f0/tests/unit/utils_tests.py

from django.test import TestCase

from oscar.core.utils import compose


class TestComposeFunction(TestCase):

    def test_composes_two_single_arg_functions(self):
        double = lambda x: 2 * x
        triple = lambda x: 3 * x

        f = compose(double, triple)
        self.assertEqual(f(2), 2 * 2 * 3)

    def test_composes_three_single_arg_functions(self):
        double = lambda x: 2 * x
        triple = lambda x: 3 * x
        quadruple = lambda x: 4 * x

        f = compose(double, triple, quadruple)
        self.assertEqual(f(2), 2 * 2 * 3 * 4)

    def test_composes_two_multi_arg_functions(self):
        double = lambda x, y: (2 * x, 2 * y)
        triple = lambda x, y: (3 * x, 3 * y)

        f = compose(double, triple)
        self.assertEqual(f(2, 4), (2 * 2 * 3, 4 * 2 * 3))