Remove "patch mock to raise for invalid assert calls"

This looks like it's causing problems with a new
mock 2.0.0 release, proposing to just remove it to
keep things working.

Closes-Bug: #1567079
Change-Id: I2a82eec20f8099c0651a21ac7aed1a0771ef5297

cinder/test.py

@@ -101,29 +101,6 @@ 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_call']
-
-            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."""
 

cinder/tests/unit/test_test.py

@@ -71,9 +71,3 @@ class MockAssertTestCase(test.TestCase):
         mock_call = mock.MagicMock(return_value=None)
         mock_call(1, 'foobar', a='123')
         mock_call.assert_called_once_with(1, 'foobar', a='123')
-
-    def test_invalid_assert_calls(self):
-        mock_call = mock.MagicMock()
-        self.assertRaises(AttributeError, lambda: mock_call.assert_called)
-        self.assertRaises(AttributeError,
-                          lambda: mock_call.assert_once_called_with)