test: upgrade backend test suite, implement unit tests, and modernize CRUD patterns

backend/tests/test_sessions_fixed.py

@@ -1,4 +1,54 @@
 import pytest
+from httpx import AsyncClient, ASGITransport
+from app.main import app
+from datetime import datetime, timezone
+
+@pytest.mark.asyncio
+async def test_create_session(api_client):
+    async with api_client as ac:
+        start_time = datetime.now(timezone.utc).isoformat()
+        payload = {"start_time": start_time}
+        response = await ac.post("/api/sessions", json=payload)
+    assert response.status_code == 201
+    data = response.json()
+    assert datetime.fromisoformat(data["start_time"]).replace(
+        tzinfo=None
+    ) == datetime.fromisoformat(start_time).replace(tzinfo=None)
+
+
+@pytest.mark.asyncio
+async def test_create_session_already_open(api_client):
+    async with api_client as ac:
+        start_time = datetime.now(timezone.utc).isoformat()
+        await ac.post("/api/sessions", json={"start_time": start_time})
+        response = await ac.post("/api/sessions", json={"start_time": start_time})
+    assert response.status_code == 409
+
+
+@pytest.mark.asyncio
+async def test_end_session(api_client):
+    async with api_client as ac:
+        start_time = datetime.now(timezone.utc).isoformat()
+        await ac.post("/api/sessions", json={"start_time": start_time})
+
+        end_time = datetime.now(timezone.utc).isoformat()
+        response = await ac.patch("/api/sessions/1/end", json={"end_time": end_time})
+
+    assert response.status_code == 200
+    assert datetime.fromisoformat(response.json()["end_time"]).replace(
+        tzinfo=None
+    ) == datetime.fromisoformat(end_time).replace(tzinfo=None)
+
+
+@pytest.mark.asyncio
+async def test_list_sessions(api_client):
+    async with api_client as ac:
+        start_time = datetime.now(timezone.utc).isoformat()
+        await ac.post("/api/sessions", json={"start_time": start_time})
+        response = await ac.get("/api/sessions")
+    assert response.status_code == 200
+    assert len(response.json()["sessions"]) >= 1
+
 from httpx import AsyncClient, ASGITransport
 from app.main import app
 from app.database import engine, init_db