anchor.diff:        var params = new AnalysisHighlightsParams.fromNotification(notification);
         if (params.file == testFile) {
           regions = params.regions;
  +        _regionsAvailable.complete(null);
         }
       }
     }
  
positive.code: @reflectiveTest
  class AnalysisNotificationHighlightsTest extends AbstractAnalysisTest {
    List<HighlightRegion> regions;
  
    @override
    bool get enableNewAnalysisDriver => false;
  
    void assertHasRawRegion(HighlightRegionType type, int offset, int length) {
      for (HighlightRegion region in regions) {
  
negative.code: 
    Future prepareHighlights() {
      addAnalysisSubscription(AnalysisService.HIGHLIGHTS, testFile);
      return _regionsAvailable.future;
    }
  
    void processNotification(Notification notification) {
  