test: process tests run outside the --parallel pool

The pool workers were made non-daemonic so the operations process
tests could start workers, but a terminated pool (Ctrl-C, --failfast)
left those workers running. The test runner now keeps the test cases
tagged "processes" out of the pool and runs them in the main process
after it. A WAL that cannot be written back before cloning now stops
the run instead of giving clones without tables. One CI leg runs the
suite with --parallel.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

.github/workflows/test.yml

@@ -95,6 +95,11 @@ jobs:
           coverage run manage.py test
           coverage report --skip-covered
 
+      # The project test runner (webvirtcloud/test_runner.py) on one leg
+      - name: Run Test Suite In Parallel
+        if: matrix.python-version == '3.13' && matrix.database == 'sqlite'
+        run: python manage.py test --parallel
+
       # The per-file report of one leg, to see what a change left untested
       - name: Store Coverage Report
         if: always() && matrix.python-version == '3.12' && matrix.database == 'sqlite'

operations/tests/test_processes.py

@@ -10,7 +10,7 @@ import time
 
 from django.contrib.auth import get_user_model
 from django.db import connections
-from django.test import TransactionTestCase
+from django.test import TransactionTestCase, tag
 
 from operations import claims, jobs
 from operations.models import Claim, Operation, WorkerLease
@@ -49,6 +49,7 @@ def _submit(user_pk, results):
     os._exit(0)
 
 
+@tag("processes")  # run outside the --parallel pool (webvirtcloud/test_runner.py)
 class ProcessTestCase(TransactionTestCase):
     def setUp(self):
         self.ctx = multiprocessing.get_context("fork")

webvirtcloud/settings.py.template

@@ -178,7 +178,7 @@ LOGIN_URL = "/accounts/login/"
 if sys.argv[1:2] == ["test"]:
     PASSWORD_HASHERS = ["django.contrib.auth.hashers.MD5PasswordHasher"]
 
-# --parallel on SQLite (WAL) and with the process tests
+# manage.py test --parallel on SQLite (WAL)
 TEST_RUNNER = "webvirtcloud.test_runner.TestRunner"
 
 # Failed logins (django-axes): a user is locked for the address the logins

webvirtcloud/test_runner.py

@@ -1,23 +1,18 @@
 """manage.py test --parallel on the SQLite database in WAL mode."""
 
-import multiprocessing
-
-from django.test.runner import DiscoverRunner, ParallelTestSuite
-
-
-def _init_worker(*args, **kwargs):
-    # Pool processes are daemonic, and a daemonic process may have no
-    # children; the operations process tests start workers of their own.
-    multiprocessing.current_process().daemon = False
-    ParallelTestSuite.init_worker(*args, **kwargs)
-
-
-class _ParallelTestSuite(ParallelTestSuite):
-    init_worker = _init_worker
+from django.test.runner import DiscoverRunner
 
 
 class TestRunner(DiscoverRunner):
-    parallel_test_suite = _ParallelTestSuite
+    def build_suite(self, *args, **kwargs):
+        suite = super().build_suite(*args, **kwargs)
+        if not isinstance(suite, self.parallel_test_suite):
+            return suite
+        # Pool workers are daemonic and may start no processes: the test
+        # cases tagged "processes" run in this process after the pool.
+        serial = [case for case in suite.subsuites if "processes" in getattr(next(iter(case)), "tags", ())]
+        suite.subsuites = [case for case in suite.subsuites if case not in serial]
+        return self.test_suite([suite, *serial])
 
     def setup_databases(self, **kwargs):
         # Django clones a SQLite test database by copying its main file, but
@@ -32,6 +27,8 @@ class TestRunner(DiscoverRunner):
             if connection.vendor == "sqlite":
                 with connection.cursor() as cursor:
                     cursor.execute("PRAGMA wal_checkpoint(TRUNCATE)")
+                    if cursor.fetchone()[0]:
+                        raise RuntimeError("The test database's WAL could not be written back before cloning")
             for index in range(parallel):
                 connection.creation.clone_test_db(
                     suffix=str(index + 1), verbosity=self.verbosity, keepdb=self.keepdb