    @Test
    public void addAll() throws Exception {

        TestKey testKey1 = new TestKey("Hello");
        TestKey testKey2 = new TestKey("World");
        TestKey testKey3 = new TestKey("Kappa");
        History history = History.of(testKey1);

        List<Object> objects = new ArrayList<>(2);
        objects.add(testKey2);
        objects.add(testKey3);

        try {
            history.addAll(objects);
            fail();
        } catch(UnsupportedOperationException e) {
            // OK!
        }
    }