feat: merge cartsnitch/api into api/ subdirectory

Consolidate API gateway service into monorepo.
Squashed from https://github.com/cartsnitch/api main (89bacb1).

Co-Authored-By: Paperclip <noreply@paperclip.ing>

tests/conftest.py

@@ -0,0 +1,101 @@
+"""Shared test fixtures with in-memory SQLite database."""
+
+import pytest
+from httpx import ASGITransport, AsyncClient
+from sqlalchemy import create_engine, event
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+from sqlalchemy.orm import sessionmaker
+
+from cartsnitch_api.config import settings as cartsnitch_settings
+from cartsnitch_api.database import get_db
+from cartsnitch_api.main import create_app
+from cartsnitch_api.models import Base
+
+TEST_DATABASE_URL = "sqlite+aiosqlite:///:memory:"
+
+
+@pytest.fixture(autouse=True)
+def disable_rate_limiting():
+    """Disable rate limiting for all tests to prevent 429 interference."""
+    cartsnitch_settings.rate_limit_enabled = False
+    yield
+    cartsnitch_settings.rate_limit_enabled = True
+
+
+@pytest.fixture
+def engine():
+    """Sync in-memory SQLite engine for model unit tests."""
+    eng = create_engine("sqlite:///:memory:")
+    Base.metadata.create_all(eng)
+    yield eng
+    eng.dispose()
+
+
+@pytest.fixture
+def session(engine):
+    """Sync SQLAlchemy session for model unit tests."""
+    factory = sessionmaker(bind=engine)
+    with factory() as sess:
+        yield sess
+
+
+@pytest.fixture
+async def db_engine():
+    engine = create_async_engine(TEST_DATABASE_URL, echo=False)
+
+    @event.listens_for(engine.sync_engine, "connect")
+    def set_sqlite_pragma(dbapi_connection, connection_record):
+        cursor = dbapi_connection.cursor()
+        cursor.execute("PRAGMA foreign_keys=ON")
+        cursor.close()
+
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)
+
+    yield engine
+
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.drop_all)
+
+    await engine.dispose()
+
+
+@pytest.fixture
+async def db_session(db_engine):
+    factory = async_sessionmaker(db_engine, class_=AsyncSession, expire_on_commit=False)
+    async with factory() as session:
+        yield session
+
+
+@pytest.fixture
+async def client(db_engine):
+    factory = async_sessionmaker(db_engine, class_=AsyncSession, expire_on_commit=False)
+
+    async def override_get_db():
+        async with factory() as session:
+            yield session
+
+    app = create_app()
+    app.dependency_overrides[get_db] = override_get_db
+
+    transport = ASGITransport(app=app)
+    async with AsyncClient(transport=transport, base_url="http://test") as ac:
+        yield ac
+
+    app.dependency_overrides.clear()
+
+
+@pytest.fixture
+async def auth_headers(client):
+    """Register a test user and return auth headers."""
+    resp = await client.post(
+        "/auth/register",
+        json={
+            "email": "test@example.com",
+            "password": "testpass123",
+            "display_name": "Test User",
+        },
+    )
+    assert resp.status_code == 201
+    token = resp.json()["access_token"]
+    return {"Authorization": f"Bearer {token}"}