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>

1 files changed, 15 insertions, 2 deletions

diff --git a/tests/runtests.py b/tests/runtests.py
index 330c8abd04..e3a60d777b 100755
--- a/tests/runtests.py
+++ b/tests/runtests.py
@@ -3,6 +3,7 @@ import argparse
 import atexit
 import copy
 import gc
+import multiprocessing
 import os
 import shutil
 import socket
@@ -10,6 +11,7 @@ import subprocess
 import sys
 import tempfile
 import warnings
+from functools import partial
 from pathlib import Path
 
 try:
@@ -24,7 +26,7 @@ else:
     from django.core.exceptions import ImproperlyConfigured
     from django.db import connection, connections
     from django.test import TestCase, TransactionTestCase
-    from django.test.runner import get_max_test_processes, parallel_type
+    from django.test.runner import _init_worker, get_max_test_processes, parallel_type
     from django.test.selenium import SeleniumTestCaseBase
     from django.test.utils import NullTimeKeeper, TimeKeeper, get_runner
     from django.utils.deprecation import RemovedInDjango50Warning
@@ -382,7 +384,8 @@ def django_tests(
             msg += " with up to %d processes" % max_parallel
         print(msg)
 
-    test_labels, state = setup_run_tests(verbosity, start_at, start_after, test_labels)
+    process_setup_args = (verbosity, start_at, start_after, test_labels)
+    test_labels, state = setup_run_tests(*process_setup_args)
     # Run the test suite, including the extra validation tests.
     if not hasattr(settings, "TEST_RUNNER"):
         settings.TEST_RUNNER = "django.test.runner.DiscoverRunner"
@@ -395,6 +398,11 @@ def django_tests(
             parallel = 1
 
     TestRunner = get_runner(settings)
+    TestRunner.parallel_test_suite.init_worker = partial(
+        _init_worker,
+        process_setup=setup_run_tests,
+        process_setup_args=process_setup_args,
+    )
     test_runner = TestRunner(
         verbosity=verbosity,
         interactive=interactive,
@@ -718,6 +726,11 @@ if __name__ == "__main__":
         options.settings = os.environ["DJANGO_SETTINGS_MODULE"]
 
     if options.selenium:
+        if multiprocessing.get_start_method() == "spawn" and options.parallel != 1:
+            parser.error(
+                "You cannot use --selenium with parallel tests on this system. "
+                "Pass --parallel=1 to use --selenium."
+            )
         if not options.tags:
             options.tags = ["selenium"]
         elif "selenium" not in options.tags: