@Before
  public void setUp() {
    mFadeDrawable = new FakeFadeDrawable(mLayers);
    mFadeDrawable.setCallback(mCallback);
  }
Tests {@link FadeDrawable} with the default configuration.

@see FadeDrawableAllOnTest for more tests
drawee/src/test/java/com/facebook/drawee/drawable/FadeDrawableTest.java