anchor.diff:  
     try {
       // Isolate Spawning another Isolate without any package specification.
  -    testNoPackages("$tmpDirPath/no_package_isolate.dart", noPackageIsolate.path,
  -        're: no package');
  +    testNoPackages("$tmpDirPath/no_package_isolate.dart",
  +        Uri.file(noPackageIsolate.path), 're: no package');
     } finally {
       tmpDir.deleteSync(recursive: true);
     }
  
positive.code:   var args = <String>[];
    args.add(mainIsolate.path);
    var result = Process.runSync(exec, args);
    expect(result.stdout.contains('$expected'), 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;
  