Day parameter seems buggy, e. g. `0 19 7 8 *` returns `2021-08-01 19:00:00`

[nilsreichardt]

Description

I tried to use this Cron: 0 19 7 8 *. This next event should be 2021-08-07 19:00:00. But this package returns 2021-08-01 19:00:00.

Test cases

import 'package:cronparse/cronparse.dart';
import 'package:test/test.dart';

void main() {
  group("Cron", () {
    final current = DateTime.parse('2021-07-11 13:00:01');

    group('.next()', () {
      test('"0 19 7 8 *" should return 7. August 2021', () {
        final cron = Cron('0 19 7 8 *');

        final next = cron.nextRelativeTo(current);
        print("next: $next");

        expect(cron.nextRelativeTo(current), DateTime.parse('2021-08-07 19:00:00'));
        // Fails ❌
      });

      test('"0 19 7 * *" should return 7. August 2021', () {
        final cron = Cron('0 19 7 * *');

        final next = cron.nextRelativeTo(current);
        print("next: $next");

        expect(cron.nextRelativeTo(current), DateTime.parse('2021-08-07 19:00:00'));
        // Fails ❌
      });

      test('"0 19 * 8 *" should return 1. August 2021', () {
        final cron = Cron('0 19 * 8 *');

        final next = cron.nextRelativeTo(current);
        print("next: $next");

        expect(cron.nextRelativeTo(current), DateTime.parse('2021-08-01 19:00:00'));
        // Pass ✅
      });
    });

    group('.previous()', () {
      test('"0 19 7 8 *" should return 7. August 2020', () {
        final cron = Cron('0 19 7 8 *');

        final previous = cron.previousRelativeTo(current);
        print("previous: $previous");

        expect(cron.previousRelativeTo(current), DateTime.parse('2020-08-07 19:00:00'));
        // Fails ❌
      });

      test('"0 19 7 * *" should return 7. July 2021', () {
        final cron = Cron('0 19 7 * *');

        final previous = cron.previousRelativeTo(current);
        print("previous: $previous");

        expect(cron.previousRelativeTo(current), DateTime.parse('2021-07-07 19:00:00'));
        // Fails ❌
      });

      test('"0 19 * 8 *" should return 31. August 2020', () {
        final cron = Cron('0 19 * 8 *');

        final previous = cron.previousRelativeTo(current);
        print("previous: $previous");

        expect(cron.previousRelativeTo(current), DateTime.parse('2020-08-31 19:00:00'));
        // Pass ✅
      });
    });
  });
}

Additional information

Flutter Version

Flutter 2.2.3 • channel stable • https://github.com/flutter/flutter.git
Framework • revision f4abaa0735 (10 days ago) • 2021-07-01 12:46:11 -0700
Engine • revision 241c87ad80
Tools • Dart 2.13.4

Cronparse version

cronparse: ^0.1.1