有人能帮我为下面的serviceImpl类编写JUnit吗

@Component
public class ProcessStatusMasterServiceImpl implements ProcessStatusMasterService {
  @Autowired
  private ProcessStatusRepository processStatusRepository;

  @Autowired
  private ApplicationContext applicationContext;

  public ProcessAndMacroStatus findProcessMaster(StatusConstant statusConstants) {
    ProcessStatusMasterService thisBean = (ProcessStatusMasterService)this.applicationContext.getBean(ProcessStatusMasterService.class);
    List<ProcessAndMacroStatus> processStatuses = thisBean.findProcessMasterByCategory(statusConstants.getCategory());
    Optional<ProcessAndMacroStatus> processStatusOpt = processStatuses.stream().filter(f -> f.getProcessAndMacroStatusKey().equals(statusConstants.getKey())).findFirst();
    if (processStatusOpt.isPresent())
      return processStatusOpt.get(); 
    throw new IllegalArgumentException("Unable to find status: " + statusConstants.getKey() + " for category: " + statusConstants.getCategory());
  }

  @Cacheable({"ProcessStatusMasterCache"})
  public List<ProcessAndMacroStatus> findProcessMasterByCategory(String category) {
    List<ProcessAndMacroStatus> processStatuses = this.processStatusRepository.findByProcessMacroStatusCategory(category);
    return processStatuses;
  }
}

下面是我正在尝试的代码，但是我得到的是when(thisBean.findProcessMasterByCategory(StatusConstant.GROUP_STATUS_SUCCESS.getCategory())).thenReturn(processStatuses);行的NPE
此变量thisbean的原因为空

@RunWith(MockitoJUnitRunner.class)
public class ProcessStatusMasterServiceImplTest {

    @Mock
    ProcessStatusRepository processStatusRepository;

    @Mock
    ApplicationContext applicationContext;

    @InjectMocks
    ProcessStatusMasterServiceImpl processStatusMasterServiceImpl;

    @Test
    public void findProcessMaster() throws Exception {
        ProcessStatusMasterService thisBean = (ProcessStatusMasterService)this.applicationContext.getBean(ProcessStatusMasterService.class);
        List<ProcessAndMacroStatus> processStatuses=new ArrayList<ProcessAndMacroStatus>();
        when(thisBean.findProcessMasterByCategory(StatusConstant.GROUP_STATUS_SUCCESS.getCategory())).thenReturn(processStatuses);

        processStatusMasterServiceImpl.findProcessMaster(StatusConstant.GROUP_STATUS_SUCCESS);

    }

}