Use expression bodied property

Author: IvenBach

Rubberduck.Core/UI/UnitTesting/TestExplorerWindow.cs

@@ -18,10 +18,7 @@ public TestExplorerWindow(TestExplorerViewModel viewModel) : this()
         public TestExplorerViewModel ViewModel { get; }
 
         // FIXME bare ClassId... not good
-        public string ClassId
-        {
-            get { return "9CF1392A-2DC9-48A6-AC0B-E601A9802608"; }
-        }
+        public string ClassId => "9CF1392A-2DC9-48A6-AC0B-E601A9802608";
 
         public string Caption => TestExplorer.TestExplorerWindow_Caption;
     }