anchor.diff:  
   library spark.workspace_test;
   
  +import 'dart:async';
   import 'dart:html';
   
   import 'package:spark_widgets/spark_dialog/spark_dialog.dart';
  
positive.code:   group('first run', () {
      test('ensure about dialog open', () {
        ModalUITester modalTester = new ModalUITester("aboutDialog");
        expect(modalTester.opened, true);
      });
  
      test('close dialog', () {
        ModalUITester modalTester = new ModalUITester("aboutDialog");
        modalTester.clickButton("done");
        expect(modalTester.opened, false);
      });
    });
  }
  
negative.code: 
    SparkDialog get dialog => getUIElement("#$id");
    SparkModal get modalElement => dialog.getShadowDomElement("#modal");
    bool get functionallyOpened => modalElement.opened;
  
    bool get visuallyOpened {
      CssStyleDeclaration style = modalElement.getComputedStyle();
      String opacity = style.opacity;
      String display = style.display;
      String visibility = style.visibility;
  
      return int.parse(opacity) > 0 && display != "none" && visibility != "visible";
    }
  
    List<SparkDialogButton> get buttons =>
        dialog.querySelectorAll("spark-dialog-button");
  
  