Fix parsing of API errors with Unicode err message (#4251)

Author: Indy2222

api_core/google/api_core/exceptions.py

@@ -378,7 +378,7 @@ def from_http_response(response):
     error_message = payload.get('error', {}).get('message', 'unknown error')
     errors = payload.get('error', {}).get('errors', ())
 
-    message = '{method} {url}: {error}'.format(
+    message = u'{method} {url}: {error}'.format(
         method=response.request.method,
         url=response.request.url,
         error=error_message)

api_core/tests/unit/test_exceptions.py

@@ -135,6 +135,22 @@ def test_from_http_response_bad_json_content():
     assert exception.message == 'POST https://example.com/: unknown error'
 
 
+def test_from_http_response_json_unicode_content():
+    response = make_response(json.dumps({
+        'error': {
+            'message': u'\u2019 message',
+            'errors': ['1', '2']
+        }
+    }).encode('utf-8'))
+
+    exception = exceptions.from_http_response(response)
+
+    assert isinstance(exception, exceptions.NotFound)
+    assert exception.code == http_client.NOT_FOUND
+    assert exception.message == u'POST https://example.com/: \u2019 message'
+    assert exception.errors == ['1', '2']
+
+
 def test_from_grpc_status():
     message = 'message'
     exception = exceptions.from_grpc_status(