@UiThreadTest public void testBack() throws Exception { FragmentManager manager = activity.getSupportFragmentManager(); FragmentStack stack = new FragmentStack(activity, manager, CONTAINER_ID); assertFalse(stack.back()); stack.push(new TestFragment1()); assertEquals(1, stack.size()); assertFalse(stack.back()); stack.push(new TestFragment1()); assertEquals(2, stack.size()); assertTrue(stack.back()); assertEquals(1, stack.size()); }