Index: Ringtoets/Integration/src/Ringtoets.Integration.Plugin/Handlers/HydraulicBoundaryDatabaseUpdateHandler.cs
===================================================================
diff -u -rb67e84a1d4c08afc280f5b0e75ef0f7909873795 -ra57f1c738b4cbc61c6e35c2d9cf2b341f1c398c1
--- Ringtoets/Integration/src/Ringtoets.Integration.Plugin/Handlers/HydraulicBoundaryDatabaseUpdateHandler.cs	(.../HydraulicBoundaryDatabaseUpdateHandler.cs)	(revision b67e84a1d4c08afc280f5b0e75ef0f7909873795)
+++ Ringtoets/Integration/src/Ringtoets.Integration.Plugin/Handlers/HydraulicBoundaryDatabaseUpdateHandler.cs	(.../HydraulicBoundaryDatabaseUpdateHandler.cs)	(revision a57f1c738b4cbc61c6e35c2d9cf2b341f1c398c1)
@@ -81,6 +81,21 @@
 
         public IEnumerable<IObservable> Update(HydraulicBoundaryDatabase hydraulicBoundaryDatabase, ReadHydraulicBoundaryDatabase readHydraulicBoundaryDatabase, ReadHydraulicLocationConfigurationDatabase readHydraulicLocationConfigurationDatabase)
         {
+            if (hydraulicBoundaryDatabase == null)
+            {
+                throw new ArgumentNullException(nameof(hydraulicBoundaryDatabase));
+            }
+
+            if (readHydraulicBoundaryDatabase == null)
+            {
+                throw new ArgumentNullException(nameof(readHydraulicBoundaryDatabase));
+            }
+
+            if (readHydraulicLocationConfigurationDatabase == null)
+            {
+                throw new ArgumentNullException(nameof(readHydraulicLocationConfigurationDatabase));
+            }
+
             throw new NotImplementedException();
         }
     }