@Test
public void testSkip() {

    RangeIterator delegate = mock(RangeIterator.class);
    RangeIteratorFacade<RangeIterator> facade = getFacade(delegate);
    CompletableFuture<Long> latch = new CompletableFuture<>();
    doAnswer(invoked -> latch.complete(invoked.getArgument(0))).when(delegate).skip(anyLong());
    final long expected = 7L;
    assertFalse("should not be done", latch.isDone());
    facade.skip(expected);
    assertEquals("should be equal", (Long) expected, latch.getNow(-1L));
}