def METHOD_NAME(self):
    pool_name = data_setup.unique_name(u'mypool%s')
    with session.begin():
        s1 = data_setup.create_system()
        s2 = data_setup.create_system()
        s3 = data_setup.create_system()
        s4 = data_setup.create_system()
        pool = data_setup.create_system_pool(name=pool_name,
                                             systems=[s1, s2, s3])
    run_client(['bkr', 'pool-remove', '--pool', pool_name,
                '--system', s1.fqdn,
                '--system', s2.fqdn])
    with session.begin():
        session.refresh(pool)
        self.assertIn(s3, pool.systems)
    # remove system from a pool of which it is not a member of
    try:
        run_client(['bkr', 'pool-remove', '--pool', pool_name,
                    '--system', s4.fqdn])
        self.fail('Must fail')
    except ClientError as e:
        self.assertIn('System %s is not in pool %s' % (s4.fqdn, pool_name),
                      e.stderr_output)