@Override
    public void clear() {
        throw MODIFICATION_ATTEMPT_ERROR;
    }
@Test
    void testClear() throws Exception {
        List<Long> list = getStateContents();
        assertThat(list).containsExactly(42L);
        assertThatThrownBy(() -> listState.clear())
                .isInstanceOf(UnsupportedOperationException.class);
    }