Merge pull request #844 from kmala/scale

fix(scale): return error message in proper format

Author: kmala

rootfs/api/models/app.py

@@ -317,7 +317,7 @@ def scale(self, user, structure):  # noqa
             for target, count in structure.copy().items():
                 structure[target] = int(count)
             validate_app_structure(structure)
-        except (TypeError, ValueError) as e:
+        except (TypeError, ValueError, ValidationError) as e:
             raise DeisException('Invalid scaling format: {}'.format(e))
 
         # test for available process types

rootfs/api/tests/test_pods.py

@@ -415,6 +415,8 @@ def test_scale_errors(self, mock_requests):
         body = {'web': -1}
         response = self.client.post(url, body)
         self.assertEqual(response.status_code, 400, response.data)
+        self.assertEqual(response.data, {"detail": "Invalid scaling format: "
+                                         "['Must be greater than or equal to zero']"})
 
         # scale to something other than a number
         url = "/v2/apps/{app_id}/scale".format(**locals())