### Question:
NetworkBfdPortService { public void updateLinkStatus(Endpoint logicalEndpoint, LinkStatus linkStatus) { log.debug("BFD-port service receive logical port status update for {} (logical) status:{}", logicalEndpoint, linkStatus); BfdPortFsm controller = lookupControllerByLogicalEndpoint(logicalEndpoint); controller.updateLinkStatus(carrier, linkStatus); } NetworkBfdPortService(IBfdPortCarrier carrier, PersistenceManager persistenceManager); void setup(Endpoint endpoint, int physicalPortNumber); Endpoint remove(Endpoint logicalEndpoint); void updateLinkStatus(Endpoint logicalEndpoint, LinkStatus linkStatus); void updateOnlineMode(Endpoint endpoint, boolean mode); void enable(Endpoint physicalEndpoint, IslReference reference); void disable(Endpoint physicalEndpoint); void speakerResponse(String key, Endpoint logicalEndpoint, BfdSessionResponse response); void speakerTimeout(String key, Endpoint logicalEndpoint);  }### Answer:
@Test public void upDownUp() { setupAndEnable(); service.updateLinkStatus(alphaLogicalEndpoint, LinkStatus.DOWN); verify(carrier).bfdDownNotification(alphaEndpoint); verifyNoMoreInteractions(carrier); reset(carrier); service.updateLinkStatus(alphaLogicalEndpoint, LinkStatus.UP); verify(carrier).bfdUpNotification(alphaEndpoint); verifyNoMoreInteractions(carrier); }