chore: import upstream snapshot with attribution

tests/http_helpers.py

@@ -0,0 +1,15 @@
+"""HTTP test helpers shared by version-related CLI tests."""
+
+import json
+from unittest.mock import MagicMock
+
+
+def mock_urlopen_response(payload: dict) -> MagicMock:
+    """Build a urlopen context-manager mock whose read returns JSON."""
+    body = json.dumps(payload).encode("utf-8")
+    resp = MagicMock()
+    resp.read.return_value = body
+    cm = MagicMock()
+    cm.__enter__.return_value = resp
+    cm.__exit__.return_value = False
+    return cm