### Question:
FlowValidationService { public List<SwitchId> getSwitchIdListByFlowId(String flowId) { return switchRepository.findSwitchesInFlowPathByFlowId(flowId).stream() .map(Switch::getSwitchId) .collect(Collectors.toList()); } FlowValidationService(PersistenceManager persistenceManager, FlowResourcesConfig flowResourcesConfig,
                                 long flowMeterMinBurstSizeInKbits, double flowMeterBurstCoefficient); void checkFlowStatus(String flowId); List<SwitchId> getSwitchIdListByFlowId(String flowId); List<FlowValidationResponse> validateFlow(String flowId, List<SwitchFlowEntries> switchFlowEntries,
                                                     List<SwitchMeterEntries> switchMeterEntries);  }### Answer:
@Test public void shouldGetSwitchIdListByFlowId() { buildTransitVlanFlow(""); List<SwitchId> switchIds = service.getSwitchIdListByFlowId(TEST_FLOW_ID_A); assertEquals(4, switchIds.size()); buildOneSwitchPortFlow(); switchIds = service.getSwitchIdListByFlowId(TEST_FLOW_ID_B); assertEquals(1, switchIds.size()); }