add url_rule for rootpath to api_test_server.py see #20

test/api_test_server.py

@@ -22,3 +22,7 @@ def passthrough():
   output = json.dumps(
     {'url': request.args, 'body': body, 'header': dict(request.headers)})
   return output
+
+@app.route('/')
+def rootpath():
+  return 'rootpath'
\ No newline at end of file