anchor.diff:    var cmd = [
       '--options',
       path.join(testDirectory, options),
  -    path.join(testDirectory, source)
  +    adjustFileSpec(source)
     ]..addAll(args);
     driver.start(cmd);
   }
  
positive.code: 
      group('build-mode', () {
        // Shared driver command.
        var testFilePath = path.join(
            path.dirname(Platform.script.toFilePath()), 'data', 'test_file.dart');
        var doDrive = () => drive('file:///test_file.dart|$testFilePath',
            args: [
              '--dart-sdk',
              findSdkDirForSummaries(),
              '--build-mode',
              '--machine'
            ],
            options: 'data/options_tests_project/.analysis_options');
  
        test('no stats', () {
          doDrive();
          // Should not print stat summary.
          expect(outSink.toString(), isEmpty);
          expect(errorSink.toString(), isEmpty);
          expect(exitCode, 0);
        });
      });
  
negative.code: List<ErrorProcessor> get processors =>
      driver.context.getConfigurationData(CONFIGURED_ERROR_PROCESSORS);
  
  /// Convert a file specification from a relative path to an absolute path.
  /// Handles the case where the file specification is of the form "$uri|$path".
  String adjustFileSpec(String fileSpec) {
    int uriPrefixLength = fileSpec.indexOf('|') + 1;
    String uriPrefix = fileSpec.substring(0, uriPrefixLength);
    String relativePath = fileSpec.substring(uriPrefixLength);
    return '$uriPrefix${path.join(testDirectory, relativePath)}';
  }
  
  /// Start a driver for the given [source], optionally providing additional
  /// [args] and an [options] file path.  The value of [options] defaults to
  /// an empty options file to avoid unwanted configuration from an otherwise
  