'The filesystem for the new ``Volume`` preserves data from the old one.'

def test_filesystem(self):

    volume = self.successResultOf(self.service.create(self.service.get(MY_VOLUME)))
    mount = volume.get_filesystem().get_path()
    mount.child('file').setContent('content')
    new_volume = self.successResultOf(volume.change_owner(self.other_node_id))
    new_mount = new_volume.get_filesystem().get_path()
    self.assertEqual(new_mount.child('file').getContent(), 'content')
