Can't set breakpoint in test

[NevRA]

I can't set breakpoint in Dartium in below code:

@TestOn("browser")
import 'package:test/test.dart';

void main() {
  group('simple tests', () {
    test("2+2", () {
      expect(2+2, 4);
    });
  });
}

It worked fine in 1.21 but since 1.23+ (maybe 1.22 too) it doesn't work.

To confirm:

1. serve project: pub serve test --port 8081
2. run test with pause: pub run test -p dartium --pub-serve=8081 test/app_test.dart --pause-after-load
3. try to set breakpoint in Dartium on line: expect(2+2, 4); and release pause in Dartium

P.S. Breakpoints in regular code works perfect.
P.P.S Issue related only for browser tests, vm tests works ok.

[avilladsen]

I've run into the same issue. I'm on Dart 1.24.2 with Dartium 50. Setting breakpoints works as expected in Chrome (version 61 beta).

Could this be a regression of #26080?

While unsuccessfully trying to find a way around it, I made a demo for this issue if that's helpful.

[zoechi]

Adding a print('xxx'); and setting a breakpoint there often works for me when other breakpoints don't work. I know, an ugly hack, but it helps to unblock.
Dartium is going away anyway.

[avilladsen]

No luck with the print('xxx'); trick.
Fair point that Dartium is going away. I'd be happy to move away from it as soon as I can replace content_shell with headless chrome (waiting on dart-lang/test#391).