@Test public void testPeek() throws Exception { subject.add("cows"); subject.add("sheep"); subject.add("ducks"); subject.add("mice"); subject.add("dogs"); subject.add("cats"); subject.add("birds"); int size = subject.size(); Assert.assertEquals(7, size); String animal = subject.peek(); Assert.assertEquals("cows", animal); size = subject.size(); Assert.assertEquals(7, size); }