testTaskUpdate function
Implementation
Future testTaskUpdate() async {
final String title = 'task - ${DateTime.now()}';
final ref = await Task.create(title: title);
final created = await Task.get(ref.id) as Task;
isTrue(created.title == title, 'title is not correct');
await created.update(title: 'new title');
final updated = await Task.get(ref.id) as Task;
isTrue(updated.title == 'new title', 'Expect: success on title update.');
}