Index: Ringtoets/Integration/src/Ringtoets.Integration.IO/Handlers/IHydraulicBoundaryDatabaseUpdateHandler.cs
===================================================================
diff -u -rb67e84a1d4c08afc280f5b0e75ef0f7909873795 -ra57f1c738b4cbc61c6e35c2d9cf2b341f1c398c1
--- Ringtoets/Integration/src/Ringtoets.Integration.IO/Handlers/IHydraulicBoundaryDatabaseUpdateHandler.cs	(.../IHydraulicBoundaryDatabaseUpdateHandler.cs)	(revision b67e84a1d4c08afc280f5b0e75ef0f7909873795)
+++ Ringtoets/Integration/src/Ringtoets.Integration.IO/Handlers/IHydraulicBoundaryDatabaseUpdateHandler.cs	(.../IHydraulicBoundaryDatabaseUpdateHandler.cs)	(revision a57f1c738b4cbc61c6e35c2d9cf2b341f1c398c1)
@@ -56,6 +56,7 @@
         /// <param name="readHydraulicBoundaryDatabase">The read hydraulic boundary database to update with.</param>
         /// <param name="readHydraulicLocationConfigurationDatabase">The read hydraulic location configuration database to update with.</param>
         /// <returns>All objects that have been affected by the update.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when any parameter is <c>null</c>.</exception>
         IEnumerable<IObservable> Update(HydraulicBoundaryDatabase hydraulicBoundaryDatabase,
                                         ReadHydraulicBoundaryDatabase readHydraulicBoundaryDatabase,
                                         ReadHydraulicLocationConfigurationDatabase readHydraulicLocationConfigurationDatabase);
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();
         }
     }
Index: Ringtoets/Integration/test/Ringtoets.Integration.Plugin.Test/Handlers/HydraulicBoundaryDatabaseUpdateHandlerTest.cs
===================================================================
diff -u -rb67e84a1d4c08afc280f5b0e75ef0f7909873795 -ra57f1c738b4cbc61c6e35c2d9cf2b341f1c398c1
--- Ringtoets/Integration/test/Ringtoets.Integration.Plugin.Test/Handlers/HydraulicBoundaryDatabaseUpdateHandlerTest.cs	(.../HydraulicBoundaryDatabaseUpdateHandlerTest.cs)	(revision b67e84a1d4c08afc280f5b0e75ef0f7909873795)
+++ Ringtoets/Integration/test/Ringtoets.Integration.Plugin.Test/Handlers/HydraulicBoundaryDatabaseUpdateHandlerTest.cs	(.../HydraulicBoundaryDatabaseUpdateHandlerTest.cs)	(revision a57f1c738b4cbc61c6e35c2d9cf2b341f1c398c1)
@@ -138,6 +138,7 @@
         [TestCase(false)]
         public void InquireConfirmation_ClickDialog_ReturnTrueIfOkAndFalseIfCancel(bool clickOk)
         {
+            // Setup
             string dialogTitle = null, dialogMessage = null;
             DialogBoxHandler = (name, wnd) =>
             {
@@ -168,5 +169,47 @@
                             "Wilt u doorgaan?",
                             dialogMessage);
         }
+
+        [Test]
+        public void Update_HydraulicBoundaryDatabaseNull_ThrowsArgumentNullException()
+        {
+            // Setup
+            var handler = new HydraulicBoundaryDatabaseUpdateHandler(new AssessmentSection(AssessmentSectionComposition.Dike));
+
+            // Call
+            TestDelegate call = () => handler.Update(null, ReadHydraulicBoundaryDatabaseTestFactory.Create(), ReadHydraulicLocationConfigurationDatabaseTestFactory.Create());
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(call);
+            Assert.AreEqual("hydraulicBoundaryDatabase", exception.ParamName);
+        }
+
+        [Test]
+        public void Update_ReadHydraulicBoundaryDatabaseNull_ThrowsArgumentNullException()
+        {
+            // Setup
+            var handler = new HydraulicBoundaryDatabaseUpdateHandler(new AssessmentSection(AssessmentSectionComposition.Dike));
+
+            // Call
+            TestDelegate call = () => handler.Update(new HydraulicBoundaryDatabase(), null, ReadHydraulicLocationConfigurationDatabaseTestFactory.Create());
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(call);
+            Assert.AreEqual("readHydraulicBoundaryDatabase", exception.ParamName);
+        }
+
+        [Test]
+        public void Update_ReadHydraulicLocationConfigurationDatabaseNull_ThrowsArgumentNullException()
+        {
+            // Setup
+            var handler = new HydraulicBoundaryDatabaseUpdateHandler(new AssessmentSection(AssessmentSectionComposition.Dike));
+
+            // Call
+            TestDelegate call = () => handler.Update(new HydraulicBoundaryDatabase(), ReadHydraulicBoundaryDatabaseTestFactory.Create(), null);
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(call);
+            Assert.AreEqual("readHydraulicLocationConfigurationDatabase", exception.ParamName);
+        }
     }
 }
\ No newline at end of file