Refactor database connection to use settings and improve test isolation with temporary DB

app/main.py

@@ -21,7 +21,6 @@ logger = logging.getLogger(__name__)
 # Database connection setup
 @asynccontextmanager
 async def lifespan(app: FastAPI):
-    conn = sqlite3.connect('urls.db')
     conn = sqlite3.connect(settings.database_url)
     conn.execute("""
     CREATE TABLE IF NOT EXISTS urls (

app/settings.py

@@ -0,0 +1,7 @@
+# app/settings.py
+
+import os
+
+# Example configuration
+database_url = os.getenv("DATABASE_URL", "sqlite:///default.db")
+debug = os.getenv("DEBUG", "True") == "True"

app/test_main.py

@@ -3,60 +3,64 @@ import sys
 import os
 
 sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
-
-from app.main import settings
+from app.main import app
+from app import settings
 import tempfile
 import pytest
 
-client = TestClient(app)
+@pytest.fixture
+def test_client():
+    with tempfile.NamedTemporaryFile() as tmp:
+        settings.database_url = tmp.name
+        with TestClient(app) as c:
+            yield c
 
-@pytest.fixture(autouse=True)
+@pytest.fixture
 def use_temp_db():
     with tempfile.NamedTemporaryFile() as tmp:
         settings.database_url = tmp.name
         yield
 
-def test_home():
-    response = client.get("/")
+def test_home(test_client):
+    response = test_client.get("/")
     assert response.status_code == 200
     assert response.json() == {"message": "URL Shortener API"}
 
-def test_shorten_url():
-    response = client.post("/shorten", json={"url": "https://google.com"})
+def test_shorten_url(test_client):
+    response = test_client.post("/shorten", json={"url": "https://google.com"})
     assert response.status_code == 200
     data = response.json()
     assert "short_url" in data
     short_url = data["short_url"]
     assert short_url.startswith("http://localhost:8000/")
 
-def test_redirect():
-    response = client.post("/shorten", json={"url": "https://google.com"})
+def test_redirect(test_client):
+    response = test_client.post("/shorten", json={"url": "https://google.com"})
     short_url = response.json()["short_url"]
     code = short_url.split("/")[-1]
 
-    redirect = client.get(f"/{code}", allow_redirects=False)
+    redirect = test_client.get(f"/{code}", follow_redirects=False)
     assert redirect.status_code == 307
 
-def test_duplicate_url_returns_same_code():
-    r1 = client.post("/shorten", json={"url": "https://example.com"})
-    r2 = client.post("/shorten", json={"url": "https://example.com"})
+def test_duplicate_url_returns_same_code(test_client):
+    r1 = test_client.post("/shorten", json={"url": "https://example.com"})
+    r2 = test_client.post("/shorten", json={"url": "https://example.com"})
 
     assert r1.status_code == 200
     assert r2.status_code == 200
     assert r1.json()["short_url"] == r2.json()["short_url"]
 
-def test_stats_endpoint():
-    response = client.post("/shorten", json={"url": "https://stats-test.com"})
+def test_stats_endpoint(test_client):
+    response = test_client.post("/shorten", json={"url": "https://stats-test.com"})
     code = response.json()["short_url"].split("/")[-1]
 
-    # trigger one redirect
-    client.get(f"/{code}", allow_redirects=False)
+    test_client.get(f"/{code}", follow_redirects=False)
 
-    stats = client.get(f"/stats/{code}")
+    stats = test_client.get(f"/stats/{code}")
     assert stats.status_code == 200
     data = stats.json()
     assert data["clicks"] == 1
 
-def test_redirect_404():
-    response = client.get("/nonexistent", allow_redirects=False)
+def test_redirect_404(test_client):
+    response = test_client.get("/nonexistent", follow_redirects=False)
     assert response.status_code == 404