Index: Ringtoets/Common/test/Ringtoets.Common.Data.Test/Calculation/CalculationGroupTest.cs
===================================================================
diff -u -rfff12e249602fb700b2854c14a3b7cdd0b73c023 -r61f2445be56feb2180cb0990d8889164c17b79f0
--- Ringtoets/Common/test/Ringtoets.Common.Data.Test/Calculation/CalculationGroupTest.cs	(.../CalculationGroupTest.cs)	(revision fff12e249602fb700b2854c14a3b7cdd0b73c023)
+++ Ringtoets/Common/test/Ringtoets.Common.Data.Test/Calculation/CalculationGroupTest.cs	(.../CalculationGroupTest.cs)	(revision 61f2445be56feb2180cb0990d8889164c17b79f0)
@@ -37,7 +37,7 @@
             var group = new CalculationGroup();
 
             // Assert
-            Assert.IsInstanceOf<CalculationGroup>(group);
+            Assert.IsInstanceOf<ICalculationBase>(group);
             Assert.IsInstanceOf<Observable>(group);
             Assert.IsTrue(group.IsNameEditable);
             Assert.AreEqual("Nieuwe map", group.Name);
@@ -56,8 +56,6 @@
             var group = new CalculationGroup(newName, isNameEditable);
 
             // Assert
-            Assert.IsInstanceOf<CalculationGroup>(group);
-            Assert.IsInstanceOf<Observable>(group);
             Assert.AreEqual(isNameEditable, group.IsNameEditable);
             Assert.AreEqual(newName, group.Name);
             CollectionAssert.IsEmpty(group.Children);