@Test
public void testSkip() throws IOException {

    int[] aDoc = { 1, 1, 2, 2 };
    int[] aStart = { 2, 4, 12, 14 };
    int[] aEnd = { 5, 7, 17, 15 };
    BLSpans a = MockSpans.withEndInPayload(aDoc, aStart, aEnd);
    Spans spans = new SpansTags(a);
    spans.advance(2);
    int[] expDoc = { 2, 2 };
    int[] expStart = { 12, 14 };
    int[] expEnd = { 17, 15 };
    Spans exp = new MockSpans(expDoc, expStart, expEnd);
    TestUtil.assertEquals(exp, spans, true);
}