def testRemovePreferredNetworkFailure(self):
    interface = 'enX'
    ssid = 'NetworkThatDoesntExist'
    args = (wifi_network_order._NETWORK_SETUP,
            '-removepreferredwirelessnetwork', interface, ssid)
    self.mox.StubOutWithMock(wifi_network_order.gmacpyutil, 'RunProcess')
    wifi_network_order.gmacpyutil.RunProcess(
        args, sudo=False, sudo_password=None).AndReturn(
            ('enX does not exist\n', 'An error occurred\n', 1))
    self.mox.ReplayAll()
    with self.assertRaises(wifi_network_order.PreferenceRemovalError):
      wifi_network_order.RemovePreferredNetwork(interface, ssid)

    self.mox.VerifyAll()
All base classes must be non-abstract
dataset/ETHPy150Open google/macops/gmacpyutil/gmacpyutil/wifi_network_order_test.py/WifiNetworkOrderModuleTest.testRemovePreferredNetworkFailure--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/tests/modeltests/proxy_models/tests.py/ProxyModelTests.test_abc