How do I mock or verify a call to print, in Dart unit tests?

In my Dart unit tests, how do I verify that print was called?

I'm writing sample code for tutorials, and I want to test it. Many samples using print for simplicity. I'd like my unit tests to verify that print is called with the right input.

Thanks!

Update: ZoneSpecification allows overriding the print function. By running code-under-test inside a custom zone you can capture calls to print function. For example, the following test redirects all print messages into an in-memory list log:

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

var log = [];

main() {
  test('override print', overridePrint(() {
    print('hello world');
    expect(log, ['hello world']);
  }));
}

void Function() overridePrint(void testFn()) => () {
  var spec = new ZoneSpecification(
    print: (_, __, ___, String msg) {
      // Add to log instead of printing to stdout
      log.add(msg);
    }
  );
  return Zone.current.fork(specification: spec).run<void>(testFn);
};