Index: Core/Common/test/Core.Common.Base.Test/ObservableListTest.cs
===================================================================
diff -u -r07f3d67fe9512b3c8303ff09398b0a234900d546 -r1f05dfdacb2bd0009e425c76495bac34a49c404a
--- Core/Common/test/Core.Common.Base.Test/ObservableListTest.cs	(.../ObservableListTest.cs)	(revision 07f3d67fe9512b3c8303ff09398b0a234900d546)
+++ Core/Common/test/Core.Common.Base.Test/ObservableListTest.cs	(.../ObservableListTest.cs)	(revision 1f05dfdacb2bd0009e425c76495bac34a49c404a)
@@ -21,6 +21,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using NUnit.Framework;
 using Rhino.Mocks;
 
@@ -43,6 +44,25 @@
         }
 
         [Test]
+        public void Observers_WhenAttachingObserver_ContainsExpectedObserver()
+        {
+            // Setup
+            var mocks = new MockRepository();
+            var testObservableList = new ObservableList<object>();
+            var observer = mocks.Stub<IObserver>();
+            testObservableList.Attach(observer);
+            mocks.ReplayAll();
+
+            // Call
+            IEnumerable<IObserver> observers = testObservableList.Observers;
+
+            // Assert
+            Assert.AreEqual(observer, observers.Single());
+
+            mocks.VerifyAll();
+        }
+
+        [Test]
         public void NotifyObservers_WithObserverAttached_ObserverIsNotified()
         {
             // Setup
Index: Core/Common/test/Core.Common.Base.Test/ObservableTest.cs
===================================================================
diff -u -r07f3d67fe9512b3c8303ff09398b0a234900d546 -r1f05dfdacb2bd0009e425c76495bac34a49c404a
--- Core/Common/test/Core.Common.Base.Test/ObservableTest.cs	(.../ObservableTest.cs)	(revision 07f3d67fe9512b3c8303ff09398b0a234900d546)
+++ Core/Common/test/Core.Common.Base.Test/ObservableTest.cs	(.../ObservableTest.cs)	(revision 1f05dfdacb2bd0009e425c76495bac34a49c404a)
@@ -21,6 +21,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using NUnit.Framework;
 using Rhino.Mocks;
 
@@ -42,6 +43,25 @@
         }
 
         [Test]
+        public void Observers_WhenAttachingObserver_ContainsExpectedObserver()
+        {
+            // Setup
+            var mocks = new MockRepository();
+            var testObservable = new TestObservable();
+            var observer = mocks.Stub<IObserver>();
+            testObservable.Attach(observer);
+            mocks.ReplayAll();
+
+            // Call
+            IEnumerable<IObserver> observers = testObservable.Observers;
+
+            // Assert
+            Assert.AreEqual(observer, observers.Single());
+
+            mocks.VerifyAll();
+        }
+
+        [Test]
         public void NotifyObservers_WithObserverAttached_ObserverIsNotified()
         {
             // Setup