Index: test/Common/DelftTools.Tests/TestObjects/Parent.cs
===================================================================
diff -u -r616892066b6752b40088bb870b4d577a2ac24ac3 -r6ddaa0a0f90fb8a5033b54988fe4fbe2dca6232b
--- test/Common/DelftTools.Tests/TestObjects/Parent.cs	(.../Parent.cs)	(revision 616892066b6752b40088bb870b4d577a2ac24ac3)
+++ test/Common/DelftTools.Tests/TestObjects/Parent.cs	(.../Parent.cs)	(revision 6ddaa0a0f90fb8a5033b54988fe4fbe2dca6232b)
@@ -1,10 +1,34 @@
 using System.Collections.Generic;
+using DelftTools.Shell.Core;
 
 namespace DelftTools.Tests.TestObjects
 {
-    public class Parent
+    public class Parent : IObservable
     {
+        private readonly IList<IObserver> observers = new List<IObserver>();
         public readonly IList<Child> Children = new List<Child>();
         public string Name { get; set; }
+
+        #region IObservable
+
+        public void Attach(IObserver observer)
+        {
+            observers.Add(observer);
+        }
+
+        public void Detach(IObserver observer)
+        {
+            observers.Remove(observer);
+        }
+
+        public void NotifyObservers()
+        {
+            foreach (var observer in observers)
+            {
+                observer.UpdateObserver();
+            }
+        }
+
+        #endregion
     }
 }
\ No newline at end of file