Merge pull request #563 from mozilla-services/enhance-if-match-error-…

…message

Enhance error message for invalid If-Match headers

cliquet/resource/__init__.py

@@ -715,9 +715,11 @@ def _raise_412_if_modified(self, record=None):
                 assert if_match[0] == if_match[-1] == '"'
                 modified_since = int(if_match[1:-1])
             except (IndexError, AssertionError, ValueError):
+                message = ("Invalid value for If-Match. The value should "
+                           "be integer between double quotes.")
                 error_details = {
                     'location': 'headers',
-                    'description': "Invalid value for If-Match"
+                    'description': message
                 }
                 raise_invalid(self.request, **error_details)
         else:

cliquet/tests/resource/test_preconditions.py

@@ -193,9 +193,12 @@ def test_delete_all_returns_412_if_changed_meanwhile(self):
                           self.resource.collection_delete)
 
     def test_if_match_without_quotes_raises_invalid(self):
-        self.resource.request.headers['If-Match'] = '123456'
-        self.assertRaises(httpexceptions.HTTPBadRequest,
-                          self.resource.collection_get)
+        with self.assertRaises(httpexceptions.HTTPBadRequest) as cm:
+            self.resource.request.headers['If-Match'] = '123456'
+            self.resource.collection_get()
+        expected_message = ('headers: Invalid value for If-Match. The value '
+                            'should be integer between double quotes.')
+        self.assertEquals(cm.exception.json['message'], expected_message)
 
     def test_if_match_empty_raises_invalid(self):
         self.resource.request.headers['If-Match'] = '""'