如何正确地将毕加索模拟成单元测试?

当我试图进行以下简单的演示者测试时

public class NewsPresenterTest {
private static List<News> NEWS_HEADLINES;

@Mock
private NewsRepository mNewsRepository;

@Mock
private Picasso mPicassoClient;

@Mock
private ChromeTabsWrapper mChromeTabsWrapper;

@Mock
private NewsContract.View mNewsView;

@Captor
private ArgumentCaptor<NewsDataSource.LoadNewsCallback> mLoadNewsCallbackCaptor;

private NewsPresenter mNewsPresenter;

@Before
public void setupNewsPresenter() {
    // inject the mocks
    MockitoAnnotations.initMocks(this);

    mNewsPresenter = new NewsPresenter(mNewsRepository, new CompositeDisposable(), mPicassoClient, mChromeTabsWrapper);
    mNewsPresenter.subscribe(mNewsView);

    NEWS_HEADLINES = Lists.newArrayList(...);
}

@Test
public void loadHeadlinesNewsFromRepositoryAndLoadIntoView(){
          // verify certain behavior 
    }
}

我似乎无法嘲笑 mPicassoClient ,结果得到以下异常:

java.lang.ExceptionInInitializerError
at sun.reflect.GeneratedSerializationConstructorAccessor3.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
...more 
Caused by: java.lang.RuntimeException: Method getMainLooper in android.os.Looper not mocked. See http://g.co/androidstudio/not-mocked for details.
at android.os.Looper.getMainLooper(Looper.java)
at com.squareup.picasso.Picasso.<clinit>(Picasso.java:109)
... and more

在堆栈状态下,启动模拟时会发生异常,这一行更准确。 MockitoAnnotations.initMocks(this);

因此嘲笑 Picasso.class 失败。我做错什么了?