id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
36946	"Running tests on SQLite with --parallel (using spawn) does not respect DATABASES[""TEST""][""NAME""]"	Sage Abdullah	Sage Abdullah	"When running unit tests on SQLite on macOS with the `--parallel` [https://docs.djangoproject.com/en/6.0/ref/django-admin/#cmdoption-test-parallel flag] and the `DATABASES[""TEST""][""NAME""]` [https://docs.djangoproject.com/en/6.0/ref/settings/#std-setting-TEST_NAME setting] set (e.g. to `mytests.db`), the tests fail to run because SQLite tries to connect to databases named `default_*.sqlite3` instead of the cloned `mytests_*.db`.

You can replicate this with the Django test suite itself, e.g. with the following change:

{{{#!diff
diff --git a/tests/test_sqlite.py b/tests/test_sqlite.py
index 0e6b0f672a..77981218fd 100644
--- a/tests/test_sqlite.py
+++ b/tests/test_sqlite.py
@@ -29,3 +29,9 @@ PASSWORD_HASHERS = [
 ]

 USE_TZ = False
+
+import os
+
+DATABASE_NAME = os.getenv(""DATABASE_NAME"")
+if DATABASE_NAME:
+    DATABASES[""default""][""TEST""] = {""NAME"": DATABASE_NAME}
}}}

and then run a subset of the tests, e.g.

{{{#!shell
DATABASE_NAME=django.db ./runtests.py --verbosity=2 --parallel=2 -- model_fields
}}}

You'll get a bunch of errors like the following:

{{{#!shell
Traceback (most recent call last):
  File ""/../python/3.14.2/lib/python3.14/multiprocessing/process.py"", line 320, in _bootstrap
    self.run()
    ~~~~~~~~^^
  File ""/../python/3.14.2/lib/python3.14/multiprocessing/process.py"", line 108, in run
    self._target(*self._args, **self._kwargs)
    ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ""/../python/3.14.2/lib/python3.14/multiprocessing/pool.py"", line 109, in worker
    initializer(*initargs)
    ~~~~~~~~~~~^^^^^^^^^^^
  File ""/django/django/test/runner.py"", line 479, in _safe_init_worker
    init_worker(counter, *args, **kwargs)
    ~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
  File ""/django/django/test/runner.py"", line 464, in _init_worker
    connection.creation.setup_worker_connection(_worker_id)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
  File ""/django/django/db/backends/sqlite3/creation.py"", line 145, in setup_worker_connection
    source_db = self.connection.Database.connect(
        f""file:{alias}_{_worker_id}.sqlite3?mode=ro"", uri=True
    )
sqlite3.OperationalError: unable to open database file
}}}

but you can see that Django successfully created/destroyed the test databases with the correct names:

{{{#!shell
Cloning test database for alias 'default' ('django.db')...
Cloning test database for alias 'default' ('django.db')...

# test results go here

Destroying test database for alias 'default' ('django_1.db')...
Destroying test database for alias 'default' ('django_2.db')...
Destroying test database for alias 'default' ('django.db')...
}}}

This also affects a multi-database setup if you set the `[""TEST""][""NAME""]` for that database. With the above example, if you run the `multiple_database` test suite (instead of `model_fields`), you won't see any errors for the `other` database; as Django will create and connect to the fallback test name based on the alias, i.e. `other_*.sqlite3`. However, if you also add `DATABASES[""other""][""TEST""] = {""NAME"": ""other_"" + DATABASE_NAME}` to the settings changes in the above example, the same error now also happens for the `other` database.

This prevents the use of custom names for running tests with `--parallel` > 1 (or `auto`), which can be particularly useful when you want to use `--keepdb` with different names. With `--parallel=1`, this issue does not occur.

I believe it is because despite the cloning was done correctly using the given test database file name in [https://github.com/django/django/blob/2de474dffca008038a7f9fe10289f390c5f4f15b/django/db/backends/sqlite3/creation.py#L58-L60 get_test_db_clone_settings], the logic in [https://github.com/django/django/blob/2de474dffca008038a7f9fe10289f390c5f4f15b/django/db/backends/sqlite3/creation.py#L145-L147 setup_worker_connection] does not use the clone db names (it always uses `{alias}_{_worker_id}.sqlite3` instead) when copying them over to the in-memory database.

FWIW, I encountered this while trying to run [https://github.com/wagtail/wagtail/pull/13922 Wagtail's test suite] in parallel with `--keepdb`. I can give a smaller reproducible example if necessary, but I think the example with Django's own test suite can be a good example too."	Bug	closed	Testing framework	dev	Normal	fixed	tests, sqlite, parallel	Sage Abdullah	Ready for checkin	1	0	0	0	0	0