@Test public void removePerson() throws Exception { // setup Room anyRoom = new Room("test"); Person somebody = new Person("somebody"); Person somebodyElse = new Person("somebodyElse"); anyRoom.addPerson(somebody); anyRoom.addPerson(somebodyElse); ArrayList listOfPeopleInRoom = anyRoom.getPeopleInRoom(); // does the people exist in the room before? assertTrue(anyRoom.getPeopleInRoom().contains(somebody)); assertTrue(anyRoom.getPeopleInRoom().contains(somebodyElse)); // remove people from room anyRoom.removePerson(somebodyElse); // is somebodyElse still in the room? assertFalse(anyRoom.getPeopleInRoom().contains(somebodyElse)); }