### Question:
AnimatorFactory { static int calcRadius(int width, int height) { return (int) Math.round(Math.sqrt((float) width * width + height * height)); } AnimatorFactory(View startView); static AnimatorFactory createFactory(View startView); abstract Animator createAppearAnimator(View targetView); abstract Animator createDisappearAnimator(View targetView);  }### Answer:
@Test public void calRadius_returns_correct_radius() throws Exception { final int radius = AnimatorFactory.calcRadius(3, 4); assertEquals(5, radius); }