private void mockBackend(boolean succeeded, EngineError errorCode) {
    doReturn(backend).when(cmd).getBackend();
    doNothing().when(cmd).startSubStep();
    doReturn(asyncTaskToBeReturned).when(cmd).handleTaskReturn(asyncTaskToBeReturned);
    doNothing().when(cmd).updateBricksWithTaskID(asyncTaskToBeReturned);

    VDSReturnValue vdsReturnValue = new VDSReturnValue();
    vdsReturnValue.setReturnValue(asyncTaskToBeReturned);
    vdsReturnValue.setSucceeded(succeeded);
    if (!succeeded) {
      vdsReturnValue.setVdsError(new VDSError(errorCode, ""));
    }
    when(vdsBrokerFrontend.runVdsCommand(
            eq(VDSCommandType.StartRemoveGlusterVolumeBricks),
            argThat(anyGlusterVolumeRemoveBricksVDSParameters())))
        .thenReturn(vdsReturnValue);
  }