The test co19/LibTest/async/Future/Future.delayed_A01_t02 looks like this (co19 rev 672):

 20 check(delayms, value) {
 21 Duration delay=durationMs(delayms);
 22 Stopwatch sw=new Stopwatch();
 23 sw.start();
 24 asyncStart();
 25 Future future = new Future.delayed(delay, (){
 26 Duration elapsed=sw.elapsed;
 27 Expect.isTrue(elapsed >= delay, "delay=$delay, elapsed=${elapsed}");
 28 asyncEnd();
 29 });
 30 }
 31
 32 main() {
 33 check(0, 11);
 34 check(300, 3);
 35 check(50, 22);
 36 }

(Note: the second argument to check is ignored)

It seems like this is a legitimate test, it calls Future.delayed() with a "delay" and asserts that the callback is only called after "delay" using a StopWatch.

This test is highly flaky on both the standalone VM and dartium (it surprised me that it's flaky on both, I would expect that standalone VM and dartium have different timer implementations).

Could someone from dartium and someone from dart:io investigate?
[Setting Area-IO, but this is dartium as well]

@floitsch: Maybe you can give some insight into the implementation of Future.delayed?