anchor.diff:      ));
       var str = FixedDateTimeFormatter('SSSSSS').encode(dateTime);
       expect(str, '001001');
  -  });
  +  }, onPlatform: skipWeb);
     test('Format SSSSSSS a microsecond', () {
       var str = FixedDateTimeFormatter('SSSSSSS')
           .encode(noFractionalSeconds.add(Duration(microseconds: 1)));
       expect(str, '0000010');
  -  });
  +  }, onPlatform: skipWeb);
     test('Format SSSSSSS 1/10 of a second', () {
       var str = FixedDateTimeFormatter('SSSSSSS')
           .encode(noFractionalSeconds.add(Duration(milliseconds: 100)));
  
positive.code:   test('Parse SSSSSS a microsecond', () {
      var time = FixedDateTimeFormatter('SSSSSS').decode('000001');
      expect(time, noFractionalSeconds.add(Duration(microseconds: 1)));
    });
    test('Parse SSSSSS a millisecond', () {
      var time = FixedDateTimeFormatter('SSSSSS').decode('001000');
      expect(time, noFractionalSeconds.add(Duration(milliseconds: 1)));
  
negative.code: 
  void main() {
    DateTime noFractionalSeconds = DateTime.utc(0, 1, 1, 0, 0, 0);
    Map<String, Skip> skipWeb = {
      'js': Skip(
          'Web does not support microseconds (see https://github.com/dart-lang/sdk/issues/44876)')
    };
    // Testing `decode`.
    test('Parse only year', () {
      var time = FixedDateTimeFormatter('YYYY').decode('1996');
  