Index: Ringtoets/ClosingStructures/test/Ringtoets.ClosingStructures.IO.Test/Configurations/ClosingStructuresCalculationConfigurationWriterTest.cs
===================================================================
diff -u -re507c88f2863ff7bc93505caf71c5f8025fb48c0 -r3a60f4df420a7669a047880a924bf4a0ff67c265
--- Ringtoets/ClosingStructures/test/Ringtoets.ClosingStructures.IO.Test/Configurations/ClosingStructuresCalculationConfigurationWriterTest.cs	(.../ClosingStructuresCalculationConfigurationWriterTest.cs)	(revision e507c88f2863ff7bc93505caf71c5f8025fb48c0)
+++ Ringtoets/ClosingStructures/test/Ringtoets.ClosingStructures.IO.Test/Configurations/ClosingStructuresCalculationConfigurationWriterTest.cs	(.../ClosingStructuresCalculationConfigurationWriterTest.cs)	(revision 3a60f4df420a7669a047880a924bf4a0ff67c265)
@@ -19,8 +19,10 @@
 // Stichting Deltares and remain full property of Stichting Deltares at all times.
 // All rights reserved.
 
+using System;
 using System.Collections.Generic;
 using System.IO;
+using Core.Common.IO.Exceptions;
 using Core.Common.TestUtil;
 using NUnit.Framework;
 using Ringtoets.ClosingStructures.IO.Configurations;
@@ -98,6 +100,28 @@
             }
         }
 
+        [Test]
+        public void Write_InvalidInflowModelType_ThrowsCriticalFileWriteException()
+        {
+            // Setup
+            var configuration = new ClosingStructuresCalculationConfiguration("fail")
+            {
+                InflowModelType = (ConfigurationClosingStructureInflowModelType?) 9000
+            };
+
+            var writer = new ClosingStructuresCalculationConfigurationWriter("valid");
+
+            // Call
+            TestDelegate call = () => writer.Write(new[]
+            {
+                configuration
+            });
+
+            // Assert
+            var exception = Assert.Throws<CriticalFileWriteException>(call);
+            Assert.IsInstanceOf<NotSupportedException>(exception.InnerException);
+        }
+
         protected override void AssertDefaultConstructedInstance(ClosingStructuresCalculationConfigurationWriter writer)
         {
             Assert.IsInstanceOf<StructureCalculationConfigurationWriter<ClosingStructuresCalculationConfiguration>>(writer);