anchor.diff:  import 'dart:html';
   import 'dart:isolate';
   
  -isolateMain() {
  +childDomIsolate() {
     port.receive((msg, replyTo) {
       if (msg != 'check') {
         replyTo.send('wrong msg: $msg');
  
positive.code:   });
  }
  
  isolateMainTrampoline() {
    final future = spawnDomFunction(isolateMain);
    port.receive((msg, parentPort) {
      future.then((childPort) {
        childPort.call(msg).then((response) {
  
negative.code:   });
  }
  
  dummy() => print('Bad invocation of top-level function');
  
  main() {
    useHtmlConfiguration();
  
    test('Simple DOM isolate test', () {
      spawnDomFunction(childDomIsolate).then((sendPort) {
        expect(sendPort.call('check'), completion('${window.location}'));
      });
    });
  
    test('Nested DOM isolates test', () {
      spawnDomFunction(trampolineIsolate).then((sendPort) {
        expect(sendPort.call('check'), completion('${window.location}'));
      });
    });
  
    test('Spawn DOM isolate from pure', () {
      expect(spawnFunction(trampolineIsolate).call('check'),
             completion('${window.location}'));
    });
  
    test('Not function', () {
  