'Calling ``from_path`` with empty instance id creates an id.'

def test_from_path_creates_instance_id_if_not_provided(self):

    loopback_blockdevice_api = LoopbackBlockDeviceAPI.from_path(root_path='')
    instance_id = loopback_blockdevice_api.compute_instance_id()
    self.assertIsInstance(instance_id, unicode)
    self.assertNotEqual(u'', instance_id)
