'Test _failover_volume.'

def test_failover_volume(self):

    self.driver.target = FakeKrest()
    session_name = self.driver.get_session_name('1234567890987654321')
    self.assertEqual('ssn-1234567890987654321', session_name)
    rsession_name = self.driver.get_rep_name(session_name)
    self.assertEqual('rssn-1234567890987654321', rsession_name)
    result = self.driver._failover_volume(self.vol)
    self.assertIsNone(result)
