anchor.diff:  
       final String testValue = 'abc def ghi';
       await tester.enterText(find.byType(EditableText), testValue);
  -    await tester.idle();
       await tester.pumpWidget(builder());
   
       // Tap the selection handle to bring up the "paste / select all" menu.
  
positive.code: 
      final String testValue = 'abc def ghi';
      await tester.enterText(find.byType(EditableText), testValue);
      await tester.idle();
      await tester.pumpWidget(builder());
  
      // Tap the selection handle to bring up the "paste / select all" menu.
  
negative.code: 
      final String testValue = 'abc def ghi';
      await tester.enterText(find.byType(EditableText), testValue);
      expect(controller.value.text, testValue);
  
      await tester.pumpWidget(builder());
  