Robolectric 3.0无法测试启动HandlerThread的函数

我有一个Job扩展HandlerThread的简单类:

public class Job extends HandlerThread{
  public Job(String name) {
     super(name);
  }
  ...
}

然后,我有一个JobUtils类,它具有获取Job&start()它的功能:

public JobUtils {
   public JobUtils() {
   }

   // I unit test this function in my test class below
   public Job getAndStartJob(String name) {
      Job job = new Job(name);
      job.start();
   }
}

我在单元测试中使用Robolectric 3.0,我测试JobUtils类的getAndStartJob(String name)功能:

@RunWith(RobolectricTestRunner.class)
public class TestJobUtils{
 @Test
 public void testGetAndStartJob() {
    JobUtils jobUtils = new JobUtils();

    // error here
    jobUtils.getAndStartJob(“test-job”);
    …
 }
}

当我运行我的单元测试代码时,我收到了错误

Exception in thread "test-job” java.lang.NullPointerException
    at org.robolectric.shadows.ShadowLooper.getMainLooper(ShadowLooper.java:70)
    at org.robolectric.shadows.ShadowLooper.doLoop(ShadowLooper.java:85)
    at org.robolectric.shadows.ShadowLooper.loop(ShadowLooper.java:76)
    at android.os.Looper.loop(Looper.java)
    at android.os.HandlerThread.run(HandlerThread.java:60)

看起来Robolectric无法启动HandlerThread(job我的代码中的实例),还是我错过了什么？如何摆脱这个问题？