anchor.diff:  
       // Reload to v2.
       var response = await slaveIsolate.reloadSources(
  -       rootLibUri: '$directory${Platform.pathSeparator}'
  -                  'complex_reload${Platform.pathSeparator}'
  -                  'v2${Platform.pathSeparator}'
  -                  'main.dart',
  +       rootLibUri: v2Uri.toString(),
       );
       expect(response['success'], isTrue);
   
  
positive.code: import 'dart:io';
  import 'service_test_common.dart';
  import 'package:observatory/service.dart';
  import 'package:unittest/unittest.dart';
  
  testMain() async {
    debugger();  // Stop here.
    // Spawn the child isolate.
    I.Isolate isolate =
        await I.Isolate.spawnUri(Uri.parse('complex_reload/v1/main.dart'),
                                 [],
                                 null);
    print(isolate);
    debugger();
  }
  
  // Directory that we are running in.
  String directory = (Platform.isWindows ? '' : Platform.pathSeparator) +
      Platform.script.pathSegments.sublist(
          0,
          Platform.script.pathSegments.length - 1).join(Platform.pathSeparator);
  
  Future<String> invokeTest(Isolate isolate) async {
    await isolate.reload();
  
negative.code: 
      // Reload to v3.
      response = await slaveIsolate.reloadSources(
        rootLibUri: v3Uri.toString(),
      );
      expect(response['success'], isTrue);
  
  