feat: add SQLite persistence models

tests/conftest.py

@@ -0,0 +1,30 @@
+import pytest
+from sqlalchemy import create_engine
+from sqlalchemy.orm import Session, sessionmaker
+from sqlalchemy.pool import StaticPool
+
+from app.db.models import Base
+from app.db.repositories import ActivityRepository, UserRepository
+
+
+@pytest.fixture
+def db_session() -> Session:
+    engine = create_engine(
+        "sqlite://",
+        connect_args={"check_same_thread": False},
+        poolclass=StaticPool,
+    )
+    Base.metadata.create_all(engine)
+    factory = sessionmaker(bind=engine, expire_on_commit=False)
+    with factory() as session:
+        yield session
+
+
+@pytest.fixture
+def user_repository(db_session: Session) -> UserRepository:
+    return UserRepository(db_session)
+
+
+@pytest.fixture
+def activity_repository(db_session: Session) -> ActivityRepository:
+    return ActivityRepository(db_session)