from contextlib import contextmanager
import os
from unittest import expectedFailure, TestSuite, TextTestRunner, defaultTestLoader

from django.test import TestCase
from django.test.runner import DiscoverRunner


def expectedFailureIf(condition):
    """Marks a test as an expected failure if ``condition`` is met."""
    if condition:
        return expectedFailure
    return lambda func: func


class DiscoverRunnerTest(TestCase):

    def test_dotted_test_module(self):
        count = DiscoverRunner().build_suite(
            ["test_discovery_sample.tests_sample"],
        ).countTestCases()

        self.assertEqual(count, 2)

    def test_dotted_test_class_vanilla_unittest(self):
        count = DiscoverRunner().build_suite(
            ["test_discovery_sample.tests_sample.TestVanillaUnittest"],
        ).countTestCases()

        self.assertEqual(count, 1)

    def test_dotted_test_class_django_testcase(self):
        count = DiscoverRunner().build_suite(
            ["test_discovery_sample.tests_sample.TestDjangoTestCase"],
        ).countTestCases()

        self.assertEqual(count, 1)

    def test_dotted_test_method_django_testcase(self):
        count = DiscoverRunner().build_suite(
            ["test_discovery_sample.tests_sample.TestDjangoTestCase.test_sample"],
        ).countTestCases()

        self.assertEqual(count, 1)

    def test_pattern(self):
        count = DiscoverRunner(
            pattern="*_tests.py",
        ).build_suite(["test_discovery_sample"]).countTestCases()

        self.assertEqual(count, 1)

    def test_file_path(self):
        @contextmanager
        def change_cwd_to_tests():
            """Change CWD to tests directory (one level up from this file)"""
            current_dir = os.path.abspath(os.path.dirname(__file__))
            tests_dir = os.path.join(current_dir, '..')
            old_cwd = os.getcwd()
            os.chdir(tests_dir)
            yield
            os.chdir(old_cwd)

        with change_cwd_to_tests():
            count = DiscoverRunner().build_suite(
                ["test_discovery_sample/"],
            ).countTestCases()

        self.assertEqual(count, 3)

    def test_overrideable_test_suite(self):
        self.assertEqual(DiscoverRunner().test_suite, TestSuite)

    def test_overrideable_test_runner(self):
        self.assertEqual(DiscoverRunner().test_runner, TextTestRunner)

    def test_overrideable_test_loader(self):
        self.assertEqual(DiscoverRunner().test_loader, defaultTestLoader)