Index: Ringtoets/HydraRing/test/Ringtoets.HydraRing.Calculation.Test/Activities/HydraRingActivityTest.cs
===================================================================
diff -u -r5e6eacaf76f765ba77febee673e9e94895e46feb -r9598b5ccb274c8aedd4d0407ef3120d82935d3fe
--- Ringtoets/HydraRing/test/Ringtoets.HydraRing.Calculation.Test/Activities/HydraRingActivityTest.cs	(.../HydraRingActivityTest.cs)	(revision 5e6eacaf76f765ba77febee673e9e94895e46feb)
+++ Ringtoets/HydraRing/test/Ringtoets.HydraRing.Calculation.Test/Activities/HydraRingActivityTest.cs	(.../HydraRingActivityTest.cs)	(revision 9598b5ccb274c8aedd4d0407ef3120d82935d3fe)
@@ -110,17 +110,14 @@
         }
 
         [Test]
-        public void Finish_OutputNull_DoesNotSetOutputAndDoesNotNotifyObservers()
+        public void Finish_OutputNull_DoesNotSetOutputAndNotifyObservers()
         {
             // Setup
             var mocks = new MockRepository();
-            var observerMock = mocks.StrictMock<IObserver>();
             var observableMock = mocks.StrictMock<IObservable>();
-            observableMock.Expect(o => o.Attach(observerMock));
+            observableMock.Expect(o => o.NotifyObservers());
             mocks.ReplayAll();
 
-            observableMock.Attach(observerMock);
-
             TestHydraRingActivity activity = new TestHydraRingActivity(true, () => null, observableMock);
 
             activity.Run();