refactor: update test fixtures and remove unused environment variables

tests/conftest.py

@@ -2,11 +2,12 @@ from collections.abc import AsyncGenerator
 from typing import Any
 
 import pytest
+from fastapi.exceptions import ResponseValidationError
 from httpx import ASGITransport, AsyncClient
 from sqlalchemy import text
-from sqlalchemy.exc import ProgrammingError
+from sqlalchemy.exc import ProgrammingError, SQLAlchemyError
 
-from app.database import engine, get_db, get_test_db, test_engine
+from app.database import engine, get_db, test_engine, TestAsyncSessionFactory
 from app.main import app
 from app.models.base import Base
 from app.redis import get_redis
@@ -43,7 +44,7 @@ def _create_db_schema(conn) -> None:
         pass
 
 
-@pytest.fixture(scope="session")
+@pytest.fixture(scope="session", autouse=True)
 async def start_db():
     # The `engine` is configured for the default 'postgres' database.
     # We connect to it and create the test database.
@@ -63,16 +64,37 @@ async def start_db():
     await test_engine.dispose()
 
 
-@pytest.fixture(scope="session")
-async def client(start_db) -> AsyncGenerator[AsyncClient, Any]:  # noqa: ARG001
+@pytest.fixture()
+async def db_session():
+    connection = await test_engine.connect()
+    transaction = await connection.begin()
+    session = TestAsyncSessionFactory(bind=connection)
+
+    try:
+        yield session
+    finally:
+        # Rollback the overall transaction, restoring the state before the test ran.
+        await session.close()
+        if transaction.is_active:
+            await transaction.rollback()
+        await connection.close()
+
+
+@pytest.fixture(scope="function")
+async def client(db_session) -> AsyncGenerator[AsyncClient, Any]:  # noqa: ARG001
     transport = ASGITransport(
         app=app,
     )
+
+    async def override_get_db():
+        yield db_session
+        await db_session.commit()
+
     async with AsyncClient(
         base_url="http://testserver/v1",
         headers={"Content-Type": "application/json"},
         transport=transport,
     ) as test_client:
-        app.dependency_overrides[get_db] = get_test_db
+        app.dependency_overrides[get_db] = override_get_db
         app.redis = await get_redis()
         yield test_client