fix: add more context to error message. (#340)

Co-authored-by: Anthonios Partheniou <[email protected]>

Author: atulep

google/api_core/path_template.py

@@ -270,7 +270,6 @@ def transcode(http_options, **request_kwargs):
         ]
         path_args = {field: get_field(request_kwargs, field) for field in path_fields}
         request["uri"] = expand(uri_template, **path_args)
-
         # Remove fields used in uri path from request
         leftovers = copy.deepcopy(request_kwargs)
         for path_field in path_fields:
@@ -297,4 +296,8 @@ def transcode(http_options, **request_kwargs):
         request["method"] = http_option["method"]
         return request
 
-    raise ValueError("Request obj does not match any template")
+    raise ValueError(
+        "Request {} does not match any URL path template in available HttpRule's {}".format(
+            request_kwargs, [opt["uri"] for opt in http_options]
+        )
+    )

tests/unit/test_path_template.py

@@ -362,6 +362,7 @@ def test_transcode_with_additional_bindings(
         [[["get", "/v1/{name}", ""]], {"name": "first/last"}],
         [[["get", "/v1/{name=mr/*/*}", ""]], {"name": "first/last"}],
         [[["post", "/v1/{name}", "data"]], {"name": "first/last"}],
+        [[["post", "/v1/{first_name}", "data"]], {"last_name": "last"}],
     ],
 )
 def test_transcode_fails(http_options, request_kwargs):
@@ -385,5 +386,4 @@ def helper_test_transcode(http_options_list, expected_result_list):
     }
     if expected_result_list[2]:
         expected_result["body"] = expected_result_list[2]
-
     return (http_options, expected_result)