assertTrue(e.skipTo(502));
assertEquals(502, e.doc());
assertEquals(1, e.nodeFreqInDoc());
assertTrue(e.nextNode());
assertEquals(node(5,3,6,3), e.node());
assertFalse(e.nextNode());
// skip to 504 and scan partially nodes
assertTrue(e.nextDocument());
assertTrue(e.nextDocument());
assertEquals(504, e.doc());