anchor.diff:    var args = <String>[];
     args.add(mainIsolate.path);
     var result = Process.runSync(exec, args);
  +  print('stdout: ${result.stdout}');
  +  print('stderr: ${result.stderr}');
     expect(result.stdout.contains('$expected'), true);
   }
   
  
positive.code: 
    try {
      // Isolate Spawning another Isolate without any package specification.
      testNoPackages("$tmpDirPath/no_package_isolate.dart", noPackageIsolate.path,
          're: no package');
    } finally {
      tmpDir.deleteSync(recursive: true);
    }
  
negative.code: import "dart:io";
  import "package:async_helper/async_minitest.dart";
  
  void testNoPackages(String filePath, Uri uri, String expected) {
    File mainIsolate = new File(filePath);
    mainIsolate.writeAsStringSync('''
      library spawn_tests;
  