immich/mobile/test/modules/utils/async_mutex_test.dart

import 'dart:async';

import 'package:flutter_test/flutter_test.dart';
import 'package:immich_mobile/utils/async_mutex.dart';

void main() {
  group('Test AsyncMutex grouped', () {
    test('test ordered execution', () async {
      AsyncMutex lock = AsyncMutex();
      List<int> events = [];
      expect(0, lock.enqueued);
      unawaited(lock.run(() => Future.delayed(const Duration(milliseconds: 10), () => events.add(1))));
      expect(1, lock.enqueued);
      unawaited(lock.run(() => Future.delayed(const Duration(milliseconds: 3), () => events.add(2))));
      expect(2, lock.enqueued);
      unawaited(lock.run(() => Future.delayed(const Duration(milliseconds: 1), () => events.add(3))));
      expect(3, lock.enqueued);
      await lock.run(() => Future.delayed(const Duration(milliseconds: 10), () => events.add(4)));
      expect(0, lock.enqueued);
      expect(events, [1, 2, 3, 4]);
    });
  });
}