diff --git a/apps/api/karrio/server/settings/base.py b/apps/api/karrio/server/settings/base.py
index ce8784434..84377e0e0 100644
--- a/apps/api/karrio/server/settings/base.py
+++ b/apps/api/karrio/server/settings/base.py
@@ -374,13 +374,7 @@
     }
 }
 
-# Speed up test suite: use fast MD5 hasher instead of bcrypt/PBKDF2
-# This only applies when running `manage.py test` — production is unaffected
-import sys as _sys
-if "test" in _sys.argv or "karrio" in _sys.argv[0]:
-    PASSWORD_HASHERS = [
-        "django.contrib.auth.hashers.MD5PasswordHasher",
-    ]
+TEST_RUNNER = "karrio.server.test_runner.KarrioTestRunner"
 
 if config("DATABASE_URL", default=None):
     db_from_env = dj_database_url.config(
diff --git a/apps/api/karrio/server/test_runner.py b/apps/api/karrio/server/test_runner.py
new file mode 100644
index 000000000..bdf371f0d
--- /dev/null
+++ b/apps/api/karrio/server/test_runner.py
@@ -0,0 +1,13 @@
+from django.conf import settings
+from django.test.runner import DiscoverRunner
+
+
+class KarrioTestRunner(DiscoverRunner):
+    """Custom Django test runner that overrides settings for the test suite."""
+
+    def setup_test_environment(self, **kwargs):
+        super().setup_test_environment(**kwargs)
+        # Speed up tests with a fast hasher (PBKDF2 is intentionally slow).
+        settings.PASSWORD_HASHERS = [
+            "django.contrib.auth.hashers.MD5PasswordHasher",
+        ]