Fixed #32591 -- Made DiscoverRunner order _FailedTest objects first.

Failures detected when loading tests are ordered before all of the
above for quicker feedback. This includes things like test modules that
couldn't be found or that couldn't be loaded due to syntax errors.

1 files changed, 10 insertions, 0 deletions

diff --git a/tests/test_runner/test_discover_runner.py b/tests/test_runner/test_discover_runner.py
index 1adb994600..366d180aa5 100644
--- a/tests/test_runner/test_discover_runner.py
+++ b/tests/test_runner/test_discover_runner.py
@@ -1,4 +1,5 @@
 import os
+import unittest.loader
 from argparse import ArgumentParser
 from contextlib import contextmanager
 from unittest import TestSuite, TextTestRunner, defaultTestLoader, mock
@@ -209,6 +210,15 @@ class DiscoverRunnerTests(SimpleTestCase):
         self.assertIn('test_2', suite[9].id(),
                       msg="Methods of unittest cases should be reversed.")
 
+    def test_build_suite_failed_tests_first(self):
+        # The "doesnotexist" label results in a _FailedTest instance.
+        suite = DiscoverRunner().build_suite(
+            test_labels=['test_runner_apps.sample', 'doesnotexist'],
+        )
+        tests = list(suite)
+        self.assertIsInstance(tests[0], unittest.loader._FailedTest)
+        self.assertNotIsInstance(tests[-1], unittest.loader._FailedTest)
+
     def test_overridable_get_test_runner_kwargs(self):
         self.assertIsInstance(DiscoverRunner().get_test_runner_kwargs(), dict)