@Test
public void testSequence_3Parsers() {

  Parser<Void> parser =
      Parsers.sequence(Scanners.isChar('a'), Scanners.isChar('b'), Scanners.isChar('c'));
  assertEquals("sequence", parser.toString());
  assertEquals(null, parser.parse("abc", mode));
  assertFailure(mode, parser, "xbc", 1, 1);
  assertFailure(mode, parser, "axc", 1, 2);
  assertFailure(mode, parser, "abx", 1, 3);
}