@Test
public void refreshCheckTasks() throws Exception {

    when(mRoomDatabase.query(anyString(), any(Object[].class)))
            .thenReturn(mock(Cursor.class));
    mTracker.refreshVersionsAsync();
    mTracker.refreshVersionsAsync();
    verify(mTaskExecutorRule.getTaskExecutor()).executeOnDiskIO(mTracker.mRefreshRunnable);
    drainTasks();
    reset(mTaskExecutorRule.getTaskExecutor());
    mTracker.refreshVersionsAsync();
    verify(mTaskExecutorRule.getTaskExecutor()).executeOnDiskIO(mTracker.mRefreshRunnable);
}