Fixed #31169 -- Adapted the parallel test runner to use spawn.

Co-authored-by: Valz <ahmadahussein0@gmail.com>
Co-authored-by: Nick Pope <nick@nickpope.me.uk>

2 files changed, 14 insertions, 6 deletions

diff --git a/tests/test_runner/test_discover_runner.py b/tests/test_runner/test_discover_runner.py
index fd36f0ab89..bca9037492 100644
--- a/tests/test_runner/test_discover_runner.py
+++ b/tests/test_runner/test_discover_runner.py
@@ -86,6 +86,16 @@ class DiscoverRunnerParallelArgumentTests(SimpleTestCase):
         mocked_cpu_count,
     ):
         mocked_get_start_method.return_value = "spawn"
+        self.assertEqual(get_max_test_processes(), 12)
+        with mock.patch.dict(os.environ, {"DJANGO_TEST_PROCESSES": "7"}):
+            self.assertEqual(get_max_test_processes(), 7)
+
+    def test_get_max_test_processes_forkserver(
+        self,
+        mocked_get_start_method,
+        mocked_cpu_count,
+    ):
+        mocked_get_start_method.return_value = "forkserver"
         self.assertEqual(get_max_test_processes(), 1)
         with mock.patch.dict(os.environ, {"DJANGO_TEST_PROCESSES": "7"}):
             self.assertEqual(get_max_test_processes(), 1)
diff --git a/tests/test_runner/tests.py b/tests/test_runner/tests.py
index 665f2c5ef8..c50c54f25c 100644
--- a/tests/test_runner/tests.py
+++ b/tests/test_runner/tests.py
@@ -480,8 +480,6 @@ class ManageCommandTests(unittest.TestCase):
 # Isolate from the real environment.
 @mock.patch.dict(os.environ, {}, clear=True)
 @mock.patch.object(multiprocessing, "cpu_count", return_value=12)
-# Python 3.8 on macOS defaults to 'spawn' mode.
-@mock.patch.object(multiprocessing, "get_start_method", return_value="fork")
 class ManageCommandParallelTests(SimpleTestCase):
     def test_parallel_default(self, *mocked_objects):
         with captured_stderr() as stderr:
@@ -507,8 +505,8 @@ class ManageCommandParallelTests(SimpleTestCase):
         # Parallel is disabled by default.
         self.assertEqual(stderr.getvalue(), "")
 
-    def test_parallel_spawn(self, mocked_get_start_method, mocked_cpu_count):
-        mocked_get_start_method.return_value = "spawn"
+    @mock.patch.object(multiprocessing, "get_start_method", return_value="spawn")
+    def test_parallel_spawn(self, *mocked_objects):
         with captured_stderr() as stderr:
             call_command(
                 "test",
@@ -517,8 +515,8 @@ class ManageCommandParallelTests(SimpleTestCase):
             )
         self.assertIn("parallel=1", stderr.getvalue())
 
-    def test_no_parallel_spawn(self, mocked_get_start_method, mocked_cpu_count):
-        mocked_get_start_method.return_value = "spawn"
+    @mock.patch.object(multiprocessing, "get_start_method", return_value="spawn")
+    def test_no_parallel_spawn(self, *mocked_objects):
         with captured_stderr() as stderr:
             call_command(
                 "test",