Finish off backend tests

tests/test_authentication.py

@@ -1,21 +1,10 @@
-import sys
-
 import pytest
 from fastapi.testclient import TestClient
 
-sys.path.append("..")
-
 from src.main import app, get_db
+from tests.base import avatar, client, password, username
 from tests.config.database import clear_db, override_get_db
 
-app.dependency_overrides[get_db] = override_get_db
-
-client = TestClient(app)
-
-username = "user1"
-password = "password"
-avatar = "lion"
-
 
 async def register_user():
     response = client.post(