@Test
  public void testFadeOutLayer() {
    // start fade out
    mFadeDrawable.setTransitionDuration(100);
    mFadeDrawable.fadeOutLayer(0);
    Assert.assertEquals(false, mFadeDrawable.mIsLayerOn[0]);
    Assert.assertEquals(false, mFadeDrawable.mIsLayerOn[1]);
    Assert.assertEquals(false, mFadeDrawable.mIsLayerOn[2]);
    Assert.assertEquals(100, mFadeDrawable.mDurationMs);
    Assert.assertEquals(FadeDrawable.TRANSITION_STARTING, mFadeDrawable.mTransitionState);
    verify(mCallback).invalidateDrawable(mFadeDrawable);
    // alphas will change only when the next draw happens
    Assert.assertEquals(255, mFadeDrawable.mAlphas[0]);
    Assert.assertEquals(0, mFadeDrawable.mAlphas[1]);
    Assert.assertEquals(0, mFadeDrawable.mAlphas[2]);
  }
Tests {@link FadeDrawable} with the default configuration.

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