@Test
public void testSequence_withMap4_fails() {

  replay();
  Parser<Integer> parser =
      Parsers.sequence(isChar('a'), isChar('b'),isChar('c'), isChar('d'), map4);
  assertFailure(mode, parser, "xbcd", 1, 1);
  assertFailure(mode, parser, "axcd", 1, 2);
  assertFailure(mode, parser, "abxd", 1, 3);
  assertFailure(mode, parser, "abcx", 1, 4);
}