使用 Robolectric 测试 ViewPager（和 CursorLoader）

Question

有人知道如何使用 Robolectric 测试以下设置吗？

包含 ViewPager 的片段，使用 CursorLoader 加载的数据。

使用下面的代码，CursorLoader 永远不会被推送到视图分页器的适配器中。 我在await() 通话中卡住了。

EventsFragmentTest.java：

@RunWith(CustomRobolectricTestRunner.class)
public class EventsFragmentTest extends AbstractDbAndUiDriver
{
    // which element in the view pager we are testing
    private static final int           TEST_INDEX = 0;

    protected SherlockFragmentActivity mActivity;
    protected EventsFragment_          mFragment;

    @Override
    @Before
    public void setUp() throws Exception
    {
        // create activity to hold the fragment
        this.mActivity = CustomRobolectricTestRunner.getActivity();

        // create and start the fragment
        this.mFragment = new EventsFragment_();
    }

    @Test
    public void sanityTest()
    {
        // create an event
        final Event event = this.createEvent();

        // create mock cursor loader
        final Cursor cursor = this.createMockEventCursor(event);
        this.mFragment.setCursorLoader(mock(CursorLoader.class));
        when(this.mFragment.getCursorLoader().loadInBackground()).thenReturn(cursor);
        CustomRobolectricTestRunner.startFragment(this.mActivity, this.mFragment);

        await().atMost(5, SECONDS).until(this.isCursorLoaderLoaded(), equalTo(true));

        // check for data displayed
        final TextView title = this.getTextView(R.id.event_view_title);
        final TextView text = this.getTextView(R.id.event_view_text);

        // exists and visible is enough for now
        this.getImageView(R.id.event_view_image);

        assertThat(title.getText().toString(), equalTo(event.getTitle()));
        assertThat(text.getText().toString(), is(event.getText()));

        // clean up
        cursor.close();
    }

    @Override
    protected View getRootView()
    {
        return ((ViewPager) this.mFragment.getView().findViewById(R.id.events_pager)).getChildAt(TEST_INDEX);
    }

    private Callable<Boolean> isCursorLoaderLoaded()
    {
        return new Callable<Boolean>()
        {
            public Boolean call() throws Exception
            {
                return EventsFragmentTest.this.mFragment.isCursorLoaderLoaded(); // The condition that must be fulfilled
            }
        };
    }

    /**
     * Create an event
     * 
     * @return
     */
    protected Event createEvent()
    {
        // create a random event
        final Event event = new Event();
        event.setImage(null);
        event.setLink("/some/link/" + RandomUtils.getRandomString(5)); //$NON-NLS-1$
        event.setResourceUri("/rest/uri/" + RandomUtils.getRandomDouble()); //$NON-NLS-1$
        event.setText("this is a test object " + RandomUtils.getRandomString(5)); //$NON-NLS-1$
        return event;
    }

    protected Cursor createMockEventCursor(final Event event)
    {
        // Create a mock cursor.
        final Cursor cursor = new CursorWrapper(mock(MockCursor.class));

        when(cursor.getCount()).thenReturn(1);
        when(cursor.getString(cursor.getColumnIndexOrThrow(EventTable.COLUMN_TEXT))).thenReturn(event.getText());
        when(cursor.getString(cursor.getColumnIndexOrThrow(EventTable.COLUMN_TITLE))).thenReturn(event.getTitle());
        when(cursor.getString(cursor.getColumnIndexOrThrow(EventTable.COLUMN_IMAGE))).thenReturn(event.getImage());
        when(cursor.getString(cursor.getColumnIndexOrThrow(EventTable.COLUMN_LINK))).thenReturn(event.getLink());
        when(cursor.getString(cursor.getColumnIndexOrThrow(EventTable.COLUMN_RESOURCE_URI))).thenReturn(
                        event.getResourceUri());

        // return created event
        return cursor;
    }

}

EventsFragment.java

@EFragment(resName = "events_fragment")
public class EventsFragment extends SherlockFragment implements LoaderCallbacks<Cursor>
{
    @ViewById(R.id.events_pager)
    protected ViewPager             mPager;

    @ViewById(R.id.events_indicator)
    protected CirclePageIndicator   mIndicator;

    @Pref
    protected ISharedPrefs_         mPreferences;

    protected EventsFragmentAdapter pageAdapter;

    private CursorLoader            mCursorLoader;

    /**
     * initialise the cursoradapter and the cursor loader manager.
     */
    @AfterViews
    void init()
    {
        final SherlockFragmentActivity activity = this.getSherlockActivity();

        this.pageAdapter = new EventsFragmentAdapter(activity.getSupportFragmentManager(), null);
        this.mPager.setAdapter(this.pageAdapter);
        this.mIndicator.setViewPager(this.mPager);
        this.getLoaderManager().initLoader(this.mPager.getId(), null, this);
    }

    /* (non-Javadoc)
     * @see android.support.v4.app.LoaderManager.LoaderCallbacks#onCreateLoader(int, android.os.Bundle)
     */
    @Override
    public Loader<Cursor> onCreateLoader(final int arg0, final Bundle arg1)
    {
        if (this.mCursorLoader == null)
        {
            // set sort to newest first
            final String sortOrder = BaseColumns._ID + " DESC"; //$NON-NLS-1$

            this.mCursorLoader = new CursorLoader(this.getActivity(), EventContentProvider.CONTENT_URI,
                            EventTable.getProjection(), AbstractDbTable.getWhereCondition(null),
                            AbstractDbTable.getWhereArgs(this.mPreferences, null), sortOrder);
        }
        return this.mCursorLoader;
    }

    /* (non-Javadoc)
     * @see android.support.v4.app.LoaderManager.LoaderCallbacks#onLoadFinished(android.support.v4.content.Loader, java.lang.Object)
     */
    @Override
    public void onLoadFinished(final Loader<Cursor> arg0, final Cursor cursor)
    {
        this.pageAdapter.swapCursor(cursor);

    }

    /* (non-Javadoc)
     * @see android.support.v4.app.LoaderManager.LoaderCallbacks#onLoaderReset(android.support.v4.content.Loader)
     */
    @Override
    public void onLoaderReset(final Loader<Cursor> arg0)
    {
        this.pageAdapter.swapCursor(null);
    }

    /**
     * Required for testing only.
     * 
     * @param cursorLoader
     */
    public void setCursorLoader(final CursorLoader cursorLoader)
    {
        this.mCursorLoader = cursorLoader;
    }

    /**
     * Required for testing only.
     * 
     * @param cursorLoader
     */
    public CursorLoader getCursorLoader()
    {
        return this.mCursorLoader;
    }

    public boolean isCursorLoaderLoaded()
    {
        return (this.pageAdapter.getCursor() != null);
    }
}

Answer 1

我不确定，但我敢打赌，内部代码正在尝试使用 AsyncTask 来调用游标加载器的 loadInBackground() 方法。您可能会看到死锁，因为 AsyncTask 尝试调用 onPostExecute()。该调用将尝试在您的主 UI 线程中运行，该线程恰好是您的测试例程的线程。这永远不会发生，因为您在调用堆栈上等待测试例程。

尝试将您的模拟提高到更高的级别，以便在测试的背景中不会真正发生任何事情。 google `AsyncTask unit test android deadlock'查看其他人遇到类似问题的示例。