'``detach_volume`` raises ``UnknownVolume`` if the supplied
``blockdevice_id`` does not exist.'

def test_detach_unknown_volume(self):

    blockdevice_id = self.unknown_blockdevice_id
    exception = self.assertRaises(UnknownVolume, self.api.detach_volume, blockdevice_id=blockdevice_id)
    self.assertEqual(exception.args, (blockdevice_id,))
