anchor.diff:  
     _invoke([Object context]) => spark._testDriver.runTests();
   }
  +
  +// analytics code
  +
  +void _handleUncaughtException(error, StackTrace stackTrace) {
  +  // We don't log the error object itself because of PII concerns.
  +  String errorDesc = error != null ? error.runtimeType.toString() : '';
  +  String desc = '${errorDesc}\n${minimizeStackTrace(stackTrace)}'.trim();
  +
  +  _analyticsTracker.sendException(desc);
  +}
  +
  +bool get _isTrackingPermitted =>
  +    _analyticsTracker.service.getConfig().isTrackingPermitted();
  +
  +set _isTrackingPermitted(bool value) =>
  +    _analyticsTracker.service.getConfig().setTrackingPermitted(value);
  
positive.code:   void initAnalytics() {
      analytics.getService('Spark').then((service) {
        // Init the analytics tracker and send a page view for the main page.
        tracker = service.getTracker(_ANALYTICS_ID);
        tracker.sendAppView('main');
        _trackLoggedExceptions();
      });
    }
  
  
negative.code: import 'lib/workspace.dart' as ws;
  import 'test/all.dart' as all_tests;
  
  analytics.Tracker _analyticsTracker = new analytics.NullTracker();
  
  void main() {
    isTestMode().then((testMode) {
      createSparkZone().runGuarded(() {
        Spark spark = new Spark(testMode);
        spark.start();
      });
  