diff --git a/backend/app/tests/api/routes/collections/test_collection_info.py b/backend/app/tests/api/routes/collections/test_collection_info.py
index 762a6654..f6ada599 100644
--- a/backend/app/tests/api/routes/collections/test_collection_info.py
+++ b/backend/app/tests/api/routes/collections/test_collection_info.py
@@ -38,7 +38,7 @@ def create_collection(
     return collection
 
 
-def test_collection_info_processing(db: Session):
+def test_collection_info_processing(db: Session, client: TestClient):
     headers = {"X-API-KEY": original_api_key}
     user = get_user_from_api_key(db, headers)
     collection = create_collection(db, user, status=CollectionStatus.processing)
@@ -57,7 +57,7 @@ def test_collection_info_processing(db: Session):
     assert data["llm_service_name"] is None
 
 
-def test_collection_info_successful(db: Session):
+def test_collection_info_successful(db: Session, client: TestClient):
     headers = {"X-API-KEY": original_api_key}
     user = get_user_from_api_key(db, headers)
     collection = create_collection(
@@ -78,7 +78,7 @@ def test_collection_info_successful(db: Session):
     assert data["llm_service_name"] == "gpt-4o"
 
 
-def test_collection_info_failed(db: Session):
+def test_collection_info_failed(db: Session, client: TestClient):
     headers = {"X-API-KEY": original_api_key}
     user = get_user_from_api_key(db, headers)
     collection = create_collection(db, user, status=CollectionStatus.failed)
diff --git a/backend/app/tests/conftest.py b/backend/app/tests/conftest.py
index 9f6fe76c..5d68c3f1 100644
--- a/backend/app/tests/conftest.py
+++ b/backend/app/tests/conftest.py
@@ -2,64 +2,60 @@
 
 import pytest
 from fastapi.testclient import TestClient
-from sqlmodel import Session, delete
+from sqlmodel import Session
+from sqlalchemy import event
 
 from app.core.config import settings
-from app.core.db import engine, init_db
+from app.core.db import engine
+from app.api.deps import get_db
 from app.main import app
-from app.models import (
-    APIKey,
-    Assistant,
-    Organization,
-    Project,
-    ProjectUser,
-    User,
-    OpenAI_Thread,
-    Credential,
-    Collection,
-)
 from app.tests.utils.user import authentication_token_from_email
 from app.tests.utils.utils import get_superuser_token_headers
 from app.seed_data.seed_data import seed_database
 
 
-@pytest.fixture(scope="session", autouse=True)
+@pytest.fixture(scope="function")
 def db() -> Generator[Session, None, None]:
-    with Session(engine) as session:
-        init_db(session)
+    connection = engine.connect()
+    transaction = connection.begin()
+    session = Session(bind=connection)
+
+    nested = session.begin_nested()
+
+    @event.listens_for(session, "after_transaction_end")
+    def restart_savepoint(sess, trans):
+        if trans.nested and not trans._parent.nested:
+            sess.begin_nested()
+
+    try:
         yield session
-        # Delete data in reverse dependency order
-        session.execute(delete(ProjectUser))  # Many-to-many relationship
-        session.execute(delete(Assistant))
-        session.execute(delete(Credential))
-        session.execute(delete(Project))
-        session.execute(delete(Organization))
-        session.execute(delete(APIKey))
-        session.execute(delete(User))
-        session.execute(delete(OpenAI_Thread))
-        session.execute(delete(Collection))
-        session.commit()
+    finally:
+        session.close()
+        transaction.rollback()
+        connection.close()
+
+
+@pytest.fixture(scope="session", autouse=True)
+def seed_baseline():
+    with Session(engine) as session:
+        seed_database(session)  # deterministic baseline
+        yield
 
 
-@pytest.fixture(scope="module")
-def client() -> Generator[TestClient, None, None]:
+@pytest.fixture(scope="function")
+def client(db: Session):
+    app.dependency_overrides[get_db] = lambda: db
     with TestClient(app) as c:
         yield c
 
 
-@pytest.fixture(scope="module")
+@pytest.fixture(scope="function")
 def superuser_token_headers(client: TestClient) -> dict[str, str]:
     return get_superuser_token_headers(client)
 
 
-@pytest.fixture(scope="module")
+@pytest.fixture(scope="function")
 def normal_user_token_headers(client: TestClient, db: Session) -> dict[str, str]:
     return authentication_token_from_email(
         client=client, email=settings.EMAIL_TEST_USER, db=db
     )
-
-
-@pytest.fixture(scope="session", autouse=True)
-def load_seed_data(db):
-    seed_database(db)
-    yield