Index: Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Plugin.Test/GrassCoverErosionOutwardsPluginTest.cs
===================================================================
diff -u -r3865311e0dac61da3aa9ca1b4645c16b90290f1e -rbc837eb44a4ee266d94e49f117b1f1f078ee94fd
--- Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Plugin.Test/GrassCoverErosionOutwardsPluginTest.cs	(.../GrassCoverErosionOutwardsPluginTest.cs)	(revision 3865311e0dac61da3aa9ca1b4645c16b90290f1e)
+++ Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Plugin.Test/GrassCoverErosionOutwardsPluginTest.cs	(.../GrassCoverErosionOutwardsPluginTest.cs)	(revision bc837eb44a4ee266d94e49f117b1f1f078ee94fd)
@@ -19,6 +19,7 @@
 // Stichting Deltares and remain full property of Stichting Deltares at all times.
 // All rights reserved.
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using Core.Common.Controls.TreeView;
@@ -136,5 +137,20 @@
                 Assert.IsNull(hydraulicBoundaryLocationExportInfo.Category);
             }
         }
+
+        [Test]
+        public void Activate_GuiNull_ThrowInvalidOperationException()
+        {
+            // Setup
+            using (var plugin = new GrassCoverErosionOutwardsPlugin())
+            {
+                // Call
+                TestDelegate test = () => plugin.Activate();
+
+                // Assert
+                var exception = Assert.Throws<InvalidOperationException>(test);
+                Assert.AreEqual("Gui cannot be null", exception.Message);
+            }
+        }
     }
 }
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