fix(fcm): Updated topic management error format (#417)

* fix(fcm): Updated topic management error format * Better default error messages * Removed redundant variable initializer

Author: hiranya911

firebase_admin/messaging.py

@@ -453,9 +453,12 @@ def _handle_iid_error(self, error):
  except ValueError:
  pass
 
- # IID error response format: {"error": "some error message"}
- msg = data.get('error')
- if not msg:
+ # IID error response format: {"error": "ErrorCode"}
+ code = data.get('error')
+ msg = None
+ if code:
+ msg = 'Error while calling the IID service: {0}'.format(code)
+ else:
  msg = 'Unexpected HTTP response with status: {0}; body: {1}'.format(
  error.response.status_code, error.response.content.decode())
 

tests/test_messaging.py

@@ -2286,7 +2286,7 @@ def test_subscribe_to_topic_error(self, status, exc_type):
  status=status, payload=self._DEFAULT_ERROR_RESPONSE)
  with pytest.raises(exc_type) as excinfo:
  messaging.subscribe_to_topic('foo', 'test-topic')
- assert str(excinfo.value) == 'error_reason'
+ assert str(excinfo.value) == 'Error while calling the IID service: error_reason'
  assert len(recorder) == 1
  assert recorder[0].method == 'POST'
  assert recorder[0].url == self._get_url('iid/v1:batchAdd')
@@ -2318,7 +2318,7 @@ def test_unsubscribe_from_topic_error(self, status, exc_type):
  status=status, payload=self._DEFAULT_ERROR_RESPONSE)
  with pytest.raises(exc_type) as excinfo:
  messaging.unsubscribe_from_topic('foo', 'test-topic')
- assert str(excinfo.value) == 'error_reason'
+ assert str(excinfo.value) == 'Error while calling the IID service: error_reason'
  assert len(recorder) == 1
  assert recorder[0].method == 'POST'
  assert recorder[0].url == self._get_url('iid/v1:batchRemove')