How can I “sleep” a Dart program

Question

I like to simulate an asynchronous web service call in my Dart application for testing. To simulate the randomness of these mock calls responding (possibly out of order) I\

Answer 1

This a useful mock that can take an optional parameter to mock an error:

  Future _mockService([dynamic error]) {
    return new Future.delayed(const Duration(seconds: 2), () {
      if (error != null) {
        throw error;
      }
    });
  }

You can use it like this:

  await _mockService(new Exception('network error'));