🚨(backend) fix InsecureKeyLengthWarning in test suite

Resolve warnings raised in jwt/api_jwt.py:365 by ensuring test
keys meet the required security length.

Align test configuration with expected cryptographic standards.

src/backend/core/tests/rooms/test_api_rooms_subtitle.py

@@ -205,7 +205,7 @@ def test_start_subtitle_wrong_signature(settings, mock_livekit_token):
     """Test that tokens signed with incorrect signature are rejected."""
 
     settings.ROOM_SUBTITLE_ENABLED = True
-    settings.LIVEKIT_CONFIGURATION["api_secret"] = "wrong-secret"
+    settings.LIVEKIT_CONFIGURATION["api_secret"] = "wrong-secret-padded-to-32-bytes!!"
 
     room = RoomFactory()
     client = APIClient()

src/backend/core/tests/rooms/test_api_rooms_webhook.py

@@ -47,7 +47,7 @@ def mock_livekit_config(settings):
     """Mock LiveKit configuration."""
     settings.LIVEKIT_CONFIGURATION = {
         "api_key": "test_api_key",
-        "api_secret": "test_api_secret",
+        "api_secret": "test_api_secret_padded_to_32bytes!",
         "url": "https://test-livekit.example.com/",
     }
     return settings.LIVEKIT_CONFIGURATION

src/backend/core/tests/test_external_api_rooms.py

@@ -713,7 +713,7 @@ def test_api_rooms_token_invalid_signature(mock_rs_authenticate, settings):
     }
     token = jwt.encode(
         payload,
-        "invalid-private-key",
+        "invalid-private-key-padded-to-32b!",
         algorithm=settings.APPLICATION_JWT_ALG,
     )
 

src/backend/meet/settings.py

@@ -981,7 +981,13 @@ class Test(Base):
     USE_SWAGGER = True
     EXTERNAL_API_ENABLED = True
 
-    APPLICATION_JWT_SECRET_KEY = "devKey"  # noqa:S105
+    LIVEKIT_CONFIGURATION = {
+        "api_key": "devkey-padded-for-minimum-len!-livekit",
+        "api_secret": "secret-key-padded-for-minimum-len!-livekit",
+        "url": "http://127.0.0.1.nip.io:7880",
+    }
+
+    APPLICATION_JWT_SECRET_KEY = "secret-key-padded-for-minimum-len!-application"  # noqa:S105
     APPLICATION_JWT_AUDIENCE = "Test inc."
 
     CELERY_TASK_ALWAYS_EAGER = True