added sample test file

Author: Harmanpreet Kaur

src/backend/middleware/test_health_check.py

@@ -0,0 +1,46 @@
+import pytest
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+from typing import Awaitable
+
+from health_check import HealthCheckMiddleware, HealthCheckResult
+
+# A sample health check function
+async def sample_check() -> HealthCheckResult:
+    return HealthCheckResult(True, "Sample check passed")
+
+# A failing health check function
+async def failing_check() -> HealthCheckResult:
+    return HealthCheckResult(False, "Sample check failed")
+
+def create_app():
+    app = FastAPI()
+
+    checks = {
+        "SampleCheck": sample_check,
+        "FailingCheck": failing_check,
+    }
+
+    app.add_middleware(HealthCheckMiddleware, checks=checks, password="testpassword")
+
+    @app.get("/")
+    async def read_root():
+        return {"message": "Hello World"}
+
+    return app
+
+@pytest.fixture
+def client():
+    app = create_app()
+    return TestClient(app)
+
+def test_healthcheck_default(client):
+    response = client.get("/healthz")
+    assert response.status_code == 503  # Failing check should result in 503
+    assert response.text == "Service Unavailable"
+
+
+def test_non_healthz_endpoint(client):
+    response = client.get("/")
+    assert response.status_code == 200
+    assert response.json() == {"message": "Hello World"}