withClock() behaves inconsistently with test()

[jamesderlin]

Consider this code:

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

void main() {
  final fakeClock = Clock.fixed(DateTime(2020, 1, 1));

  test('inner withClock', () {
    withClock(fakeClock, () {
      expect(clock, same(fakeClock));
    });
  });

  withClock(fakeClock, () {
    test('outer withClock', () {
      expect(clock, same(fakeClock));
    });
  });
}

I don't see anything in the withClock documentation that indicates whether one form is preferred over the other. When I run this with dart this_test.dart, I get:

00:00 +0: inner withClock
00:00 +1: outer withClock
00:00 +1 -1: outer withClock [E]

  Expected: same instance as <Instance of 'Clock'>
    Actual: <Instance of 'Clock'>

More weirdness, part 1

If I reverse the tests, they pass when running it through dart.

More weirdness, part 2

The "outer withClock" test by itself fails with flutter test or with pub run test. Each test passes individually when run directly through dart.

Ultimately I'd like to do:

withClock(fakeClock, () {
  test(...);
  test(...);
  test(...);
});

but all of this weirdness seems to prevent that.

(I'm using Dart 2.8.1 with clock 1.0.1.)

[jamesderlin]

I think that this is dart-lang/test#1023. The test callbacks don't run in the same Zone as when test() was executed.

[jamesderlin]

I still don't understand how the "outer withClock" test ever works at all, but I care a lot less about that knowing that I shouldn't expect it to work.