Raise exception for invalid mock assert calls

Several test cases were using the wrong mock assert methods.
The following patch corrects these calls and adds a method in
test.py (sourced from nova/test.py) to make sure they are
properly caught in the future.

Closes-Bug: #1429669
Change-Id: Ic6e5bca0c3ddbfb402e412b51e882859cb49108c

cinder/test.py

@@ -100,6 +100,29 @@ class Database(fixtures.Fixture):
                 os.path.join(CONF.state_path, self.sqlite_db))
 
 
+def _patch_mock_to_raise_for_invalid_assert_calls():
+    def raise_for_invalid_assert_calls(wrapped):
+        def wrapper(_self, name):
+            valid_asserts = [
+                'assert_called_with',
+                'assert_called_once_with',
+                'assert_has_calls',
+                'assert_any_calls']
+
+            if name.startswith('assert') and name not in valid_asserts:
+                raise AttributeError('%s is not a valid mock assert method'
+                                     % name)
+
+            return wrapped(_self, name)
+        return wrapper
+    mock.Mock.__getattr__ = raise_for_invalid_assert_calls(
+        mock.Mock.__getattr__)
+
+# NOTE(gibi): needs to be called only once at import time
+# to patch the mock lib
+_patch_mock_to_raise_for_invalid_assert_calls()
+
+
 class TestCase(testtools.TestCase):
     """Test case base class for all unit tests."""