test_image_metadata makes assumptions about images

This test fails for me as follows. The test seems to assume that images start with no metadata. My image was a uec image which I guess has some metadata already because the test fails:

Traceback (most recent call last):
  File "/root/tempest/tempest/tests/test_image_metadata.py", line 92, in test_delete_image_metadata_item
    self.assertEqual(expected, resp_metadata)
AssertionError: {'key2': 'value2'} != {u'owner': None, u'key2': u'value2', u'min_ram': u'0', u'min_disk': u'0'}
- {'key2': 'value2'}
+ {u'key2': u'value2', u'min_disk': u'0', u'min_ram': u'0', u'owner': None}

The test should have a start point of existing metadata, or check for the presence or absence of items after actions rather than comparing for equality.