@SpringBootTest decorator causes test to get stuck for WatchService

I have simple application which I want to use to watch over a directory, the way I have done it so far is by using WatchService class:

ApplicationClass:

@SpringBootApplication
public class MmsdirectorywatcherApplication {

    public static void main(String[] args) {
        SpringApplication.run(MmsdirectorywatcherApplication.class, args);
    }

    @Autowired
    DirectoryWatcher directoryWatcher;

    @Bean
    public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
        return args -> {
            directoryWatcher.startWatching();
        };
    }

}

DirectoryWatcher:

@Component
public class DirectoryWatcher {

    WatchService watchService;
    Path path;
    private String watcherDiretory;

    public DirectoryWatcher() {
    }


    @Value("${mms.directorywatcher.directory}")
    public void setWatcherDiretory(String watcherDiretory) {
        this.watcherDiretory = watcherDiretory;
    }

    public void startWatching(){
        path = Paths.get(watcherDiretory);
        try{
            watchService
                    = FileSystems.getDefault().newWatchService();

            path.register(
                    watchService,
                    StandardWatchEventKinds.ENTRY_CREATE,
                    StandardWatchEventKinds.ENTRY_DELETE,
                    StandardWatchEventKinds.ENTRY_MODIFY);

            WatchKey key;
            while ((key = watchService.take()) != null) {
                for (WatchEvent<?> event : key.pollEvents()) {
                    System.out.println(
                            "Event kind:" + event.kind()
                                    + ". File affected: " + event.context() + ".");
                }
                key.reset();
            }
        }
        catch (IOException ex){

        }
        catch (InterruptedException ex){

        }


    }
}

This run fine, but I want to test if the applicationStarted correctly, here is the test:

@SpringBootTest(classes = {MmsdirectorywatcherApplication.class})
class MmsdirectorywatcherApplicationTests {
    @Autowired
    private DirectoryWatcher directoryWatcher;
    @Test
    void contextLoads() {
        assertNotNull(directoryWatcher);
    }

}

When I run the test it seems like its stuck like something is blocking it from completion. May be it the watchService itself, but I am not sure how to get around this as I do want to eventually test if startWatching is been called.

Thanks for you time

Your context start calls startWatching(), and that function just never returns. Note that watchService.take() will block until an event comes in.