Adjust tox invocation of test execution.

Author: charettes

tox.ini

@@ -14,8 +14,10 @@ basepython =
     py313: python3.13
     py314: python3.14
 usedevelop = true
+setenv =
+    DJANGO_SETTINGS_MODULE=tests.settings
 commands =
-    coverage run {envbindir}/django-admin test -v2 --settings=tests.settings {posargs}
+    {envpython} -R -Wonce {envbindir}/coverage run -a -m django test -v2 {posargs}
     coverage report
 deps =
     coverage