test.test_api_usage: fix secscan tests

util/secscan/fake.py

@@ -5,6 +5,7 @@ import urlparse
 
 from contextlib import contextmanager
 from httmock import urlmatch, HTTMock, all_requests
+
 from util.secscan.api import UNKNOWN_PARENT_LAYER_ERROR_MSG, compute_layer_id
 
 @contextmanager
@@ -170,7 +171,6 @@ class FakeSecurityScanner(object):
 
   def get_endpoints(self):
     """ Returns the HTTMock endpoint definitions for the fake security scanner. """
-
     @urlmatch(netloc=r'(.*\.)?' + self.hostname, path=r'/v1/layers/(.+)', method='GET')
     def get_layer_mock(url, request):
       layer_id = url.path[len('/v1/layers/'):]
@@ -320,7 +320,7 @@ class FakeSecurityScanner(object):
     def response_content(url, _):
       return {
         'status_code': 500,
-        'content': '',
+        'content': json.dumps({'Error': {'Message': 'Unknown endpoint %s' % url.path}}),
       }
 
     return [get_layer_mock, post_layer_mock, remove_layer_mock, get_notification,