with some tests

backend/tests/test_counter.py

@@ -0,0 +1,60 @@
+import pytest
+from httpx import ASGITransport, AsyncClient
+from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker
+
+from database import Base, get_db
+from main import app
+
+TEST_DATABASE_URL = "sqlite+aiosqlite:///:memory:"
+
+
+@pytest.fixture
+async def client():
+    engine = create_async_engine(TEST_DATABASE_URL)
+    async_session = async_sessionmaker(engine, expire_on_commit=False)
+
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)
+
+    async def override_get_db():
+        async with async_session() as session:
+            yield session
+
+    app.dependency_overrides[get_db] = override_get_db
+
+    async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as c:
+        yield c
+
+    app.dependency_overrides.clear()
+    await engine.dispose()
+
+
+@pytest.mark.asyncio
+async def test_get_counter_initial(client):
+    response = await client.get("/api/counter")
+    assert response.status_code == 200
+    assert response.json() == {"value": 0}
+
+
+@pytest.mark.asyncio
+async def test_increment_counter(client):
+    response = await client.post("/api/counter/increment")
+    assert response.status_code == 200
+    assert response.json() == {"value": 1}
+
+
+@pytest.mark.asyncio
+async def test_increment_counter_multiple(client):
+    await client.post("/api/counter/increment")
+    await client.post("/api/counter/increment")
+    response = await client.post("/api/counter/increment")
+    assert response.json() == {"value": 3}
+
+
+@pytest.mark.asyncio
+async def test_get_counter_after_increment(client):
+    await client.post("/api/counter/increment")
+    await client.post("/api/counter/increment")
+    response = await client.get("/api/counter")
+    assert response.json() == {"value": 2}
+