Add "Simple web server" challenge (#74)

Co-authored-by: Silen Naihin <silen.naihin@gmail.com>

agbenchmark/challenges/code/d3/custom_python/api_tests.py

@@ -0,0 +1,27 @@
+import os
+from typing import Any, Dict
+from unittest.mock import Mock, patch
+
+import requests
+
+
+def make_assertion() -> None:
+    if os.environ.get("MOCK_TEST", "False").lower() == "true":
+        mock_response = Mock(requests.Response)
+        mock_response.status_code = 200
+        mock_response.json.return_value = {"status": "OK"}
+
+        with patch("requests.get", return_value=mock_response):
+            make_request_and_assert()
+    else:
+        make_request_and_assert()
+
+
+def make_request_and_assert() -> Dict[str, Any]:
+    response = requests.get("http://localhost:8079/health")
+    if response.status_code != 200:
+        raise AssertionError(
+            f"Expected status code 200, but got {response.status_code}"
+        )
+
+    return response.json()