Index: Core/Common/test/Core.Common.Controls.TreeView.Test/TreeViewControlTest.cs
===================================================================
diff -u -r851a4fd176950c1d9fae55847218fe1e0e715012 -re8b38c279ab010c360bd6589c8600e9cf387b11f
--- Core/Common/test/Core.Common.Controls.TreeView.Test/TreeViewControlTest.cs	(.../TreeViewControlTest.cs)	(revision 851a4fd176950c1d9fae55847218fe1e0e715012)
+++ Core/Common/test/Core.Common.Controls.TreeView.Test/TreeViewControlTest.cs	(.../TreeViewControlTest.cs)	(revision e8b38c279ab010c360bd6589c8600e9cf387b11f)
@@ -253,21 +253,22 @@
                 treeViewControl.Data = dataObject;
                 treeViewControl.NodeUpdated += (s, e) => hit++;
 
-                // Call
-                Action test = () =>
-                {
-                    treeViewControl.TryRenameNodeForData(dataObject);
-                };
-
-                // Assert
+                string messageBoxText = null;
                 DialogBoxHandler = (name, wnd) =>
                 {
                     var helper = new MessageBoxTester(wnd);
-                    Assert.AreEqual(Properties.Resources.TreeViewControl_The_selected_item_cannot_be_renamed, helper.Text);
+
+                    messageBoxText = helper.Text;
+
                     helper.ClickOk();
                 };
-                test();
+
+                // Call
+                treeViewControl.TryRenameNodeForData(dataObject);
+
+                // Assert
                 Assert.AreEqual(0, hit);
+                Assert.AreEqual(Properties.Resources.TreeViewControl_The_selected_item_cannot_be_renamed, messageBoxText);
             }
         }
 
@@ -399,22 +400,24 @@
                 var dataObject = new object();
                 treeViewControl.Data = dataObject;
 
-                // Call
-                Action test = () =>
-                {
-                    treeViewControl.TryRemoveNodeForData(dataObject);
-                };
-
-                // Assert
+                string messageBoxText = null;
                 DialogBoxHandler = (name, wnd) =>
                 {
                     var helper = new MessageBoxTester(wnd);
-                    Assert.AreEqual(Properties.Resources.TreeViewControl_The_selected_item_cannot_be_removed, helper.Text);
+
+                    messageBoxText = helper.Text;
+
                     helper.ClickOk();
                 };
-                test();
+
+                // Call
+                treeViewControl.TryRemoveNodeForData(dataObject);
+
+                // Assert
                 Assert.AreEqual(0, onNodeRemovedHit);
                 Assert.AreEqual(0, onDataDeletedHit);
+
+                Assert.AreEqual(Properties.Resources.TreeViewControl_The_selected_item_cannot_be_removed, messageBoxText);
             }
         }
 
@@ -442,23 +445,24 @@
                 {
                     WindowsFormsTestHelper.Show(treeViewControl);
 
-                    // Call
-                    Action test = () =>
-                    {
-                        treeViewControl.TryRemoveNodeForData(dataObject);
-                    };
-
-                    // Assert
+                    string messageBoxText = null;
                     DialogBoxHandler = (name, wnd) =>
                     {
                         var helper = new MessageBoxTester(wnd);
-                        Assert.AreEqual(Properties.Resources.TreeViewControl_Are_you_sure_you_want_to_remove_the_selected_item, helper.Text);
+
+                        messageBoxText = helper.Text;
+
                         helper.ClickOk();
                     };
-                    test();
 
+                    // Call
+                    treeViewControl.TryRemoveNodeForData(dataObject);
+
+                    // Assert
                     Assert.AreEqual(1, onNodeRemovedHit);
                     Assert.AreEqual(1, onDataDeletedHit);
+
+                    Assert.AreEqual(Properties.Resources.TreeViewControl_Are_you_sure_you_want_to_remove_the_selected_item, messageBoxText);
                 }
                 finally
                 {
@@ -489,22 +493,23 @@
                 {
                     WindowsFormsTestHelper.Show(treeViewControl);
 
-                    // Call
-                    Action test = () =>
-                    {
-                        treeViewControl.TryRemoveNodeForData(dataObject);
-                    };
-
-                    // Assert
+                    string messageBoxText = null;
                     DialogBoxHandler = (name, wnd) =>
                     {
                         var helper = new MessageBoxTester(wnd);
-                        Assert.AreEqual(Properties.Resources.TreeViewControl_Are_you_sure_you_want_to_remove_the_selected_item, helper.Text);
+
+                        messageBoxText = helper.Text;
+
                         helper.ClickCancel();
                     };
-                    test();
 
+                    // Call
+                    treeViewControl.TryRemoveNodeForData(dataObject);
+
+                    // Assert
                     Assert.AreEqual(0, hit);
+
+                    Assert.AreEqual(Properties.Resources.TreeViewControl_Are_you_sure_you_want_to_remove_the_selected_item, messageBoxText);
                 }
                 finally
                 {
Index: Core/Common/test/Core.Common.Integration.Test/Ringtoets/Application.Ringtoets/GuiImportHandlerTest.cs
===================================================================
diff -u -r791e86bf9004a55178386416eb6a9c545380bd1c -re8b38c279ab010c360bd6589c8600e9cf387b11f
--- Core/Common/test/Core.Common.Integration.Test/Ringtoets/Application.Ringtoets/GuiImportHandlerTest.cs	(.../GuiImportHandlerTest.cs)	(revision 791e86bf9004a55178386416eb6a9c545380bd1c)
+++ Core/Common/test/Core.Common.Integration.Test/Ringtoets/Application.Ringtoets/GuiImportHandlerTest.cs	(.../GuiImportHandlerTest.cs)	(revision e8b38c279ab010c360bd6589c8600e9cf387b11f)
@@ -15,23 +15,32 @@
         [Test]
         public void NoImporterAvailableGivesMessageBox()
         {
+            // Setup
             var applicationCore = new ApplicationCore();
             
             var mocks = new MockRepository();
             var mainWindow = mocks.Stub<IMainWindow>();
             mocks.ReplayAll();
 
+            string messageBoxTitle = null, messageBoxText = null;
             DialogBoxHandler = (name, wnd) =>
             {
                 var messageBox = new MessageBoxTester(wnd);
-                Assert.AreEqual("Geen enkele 'Importer' is beschikbaar voor dit element.", messageBox.Text);
-                Assert.AreEqual("Fout", messageBox.Title);
+
+                messageBoxText = messageBox.Text;
+                messageBoxTitle = messageBox.Title;
+
                 messageBox.ClickOk();
             };
 
             var importHandler = new GuiImportHandler(mainWindow, applicationCore);
 
+            // Call
             importHandler.ImportDataTo(typeof(Int64));
+
+            // Assert
+            Assert.AreEqual("Fout", messageBoxTitle);
+            Assert.AreEqual("Geen enkele 'Importer' is beschikbaar voor dit element.", messageBoxText);
         }
     }
 }
\ No newline at end of file
Index: Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/TreeNodeInfos/PipingCalculationContextTreeNodeInfoTest.cs
===================================================================
diff -u -rded51ed5be07b08a299605abbeaed5ba70a7f89c -re8b38c279ab010c360bd6589c8600e9cf387b11f
--- Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/TreeNodeInfos/PipingCalculationContextTreeNodeInfoTest.cs	(.../PipingCalculationContextTreeNodeInfoTest.cs)	(revision ded51ed5be07b08a299605abbeaed5ba70a7f89c)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/TreeNodeInfos/PipingCalculationContextTreeNodeInfoTest.cs	(.../PipingCalculationContextTreeNodeInfoTest.cs)	(revision e8b38c279ab010c360bd6589c8600e9cf387b11f)
@@ -490,14 +490,17 @@
 
             mocks.ReplayAll();
 
-            DialogBoxHandler = (name, wnd) => { };
-
             plugin.Gui = gui;
 
             calculation.Attach(observer);
 
             var contextMenuAdapter = info.ContextMenuStrip(pipingCalculationContext, null, treeViewControlMock);
 
+            DialogBoxHandler = (name, wnd) =>
+            {
+                // Don't care about dialogs in this test.
+            };
+
             // When
             Action action = () => { contextMenuAdapter.Items[calculateContextMenuItemIndex].PerformClick(); };
 
@@ -584,8 +587,6 @@
 
             mocks.ReplayAll();
 
-            DialogBoxHandler = (name, wnd) => { };
-
             plugin.Gui = gui;
 
             calculation.InputParameters.AssessmentLevel = validPipingInput.AssessmentLevel;
@@ -616,6 +617,11 @@
 
             var contextMenuAdapter = info.ContextMenuStrip(pipingCalculationContext, null, treeViewControlMock);
 
+            DialogBoxHandler = (name, wnd) =>
+            {
+                // Don't care about dialogs in this test.
+            };
+
             // When
             Action action = () => { contextMenuAdapter.Items[calculateContextMenuItemIndex].PerformClick(); };
 
@@ -671,11 +677,12 @@
 
             var contextMenuAdapter = info.ContextMenuStrip(pipingCalculationContext, null, treeViewControlMock);
 
+            string messageBoxText = null, messageBoxTitle = null;
             DialogBoxHandler = (name, wnd) =>
             {
                 var messageBox = new MessageBoxTester(wnd);
-                Assert.AreEqual("Weet u zeker dat u de uitvoer van deze berekening wilt wissen?", messageBox.Text);
-                Assert.AreEqual("Bevestigen", messageBox.Title);
+                messageBoxText = messageBox.Text;
+                messageBoxTitle = messageBox.Title;
                 if (confirm)
                 {
                     messageBox.ClickOk();
@@ -691,7 +698,8 @@
 
             // Then
             Assert.AreNotEqual(confirm, calculation.HasOutput);
-
+            Assert.AreEqual("Bevestigen", messageBoxTitle);
+            Assert.AreEqual("Weet u zeker dat u de uitvoer van deze berekening wilt wissen?", messageBoxText);
             mocks.VerifyAll();
         }
     }
Index: Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/TreeNodeInfos/PipingCalculationGroupContextTreeNodeInfoTest.cs
===================================================================
diff -u -rdc41fb966f99f5200c570d70e16397087ffa87c8 -re8b38c279ab010c360bd6589c8600e9cf387b11f
--- Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/TreeNodeInfos/PipingCalculationGroupContextTreeNodeInfoTest.cs	(.../PipingCalculationGroupContextTreeNodeInfoTest.cs)	(revision dc41fb966f99f5200c570d70e16397087ffa87c8)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/TreeNodeInfos/PipingCalculationGroupContextTreeNodeInfoTest.cs	(.../PipingCalculationGroupContextTreeNodeInfoTest.cs)	(revision e8b38c279ab010c360bd6589c8600e9cf387b11f)
@@ -719,10 +719,13 @@
 
             plugin.Gui = gui;
 
-            DialogBoxHandler = (name, wnd) => { };
-
             var contextMenu = info.ContextMenuStrip(nodeData, null, treeViewControl);
 
+            DialogBoxHandler = (name, wnd) =>
+            {
+                // Don't care about dialogs in this test.
+            };
+
             // Call
             contextMenu.Items[contextMenuCalculateAllIndex].PerformClick();
 
@@ -781,11 +784,14 @@
 
             plugin.Gui = gui;
 
+            string messageBoxTitle = null, messageBoxText = null;
             DialogBoxHandler = (name, wnd) =>
             {
                 var messageBox = new MessageBoxTester(wnd);
-                Assert.AreEqual("Weet u zeker dat u alle uitvoer wilt wissen?", messageBox.Text);
-                Assert.AreEqual("Bevestigen", messageBox.Title);
+
+                messageBoxText = messageBox.Text;
+                messageBoxTitle = messageBox.Title;
+
                 if (confirm)
                 {
                     messageBox.ClickOk();
@@ -808,6 +814,9 @@
             Assert.AreNotEqual(confirm, @group.HasOutput);
             Assert.AreNotEqual(confirm, calculation1.HasOutput);
             Assert.AreNotEqual(confirm, calculation2.HasOutput);
+
+            Assert.AreEqual("Bevestigen", messageBoxTitle);
+            Assert.AreEqual("Weet u zeker dat u alle uitvoer wilt wissen?", messageBoxText);
             mocks.VerifyAll();
         }
 
Index: Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/TreeNodeInfos/PipingFailureMechanismTreeNodeInfoTest.cs
===================================================================
diff -u -rf98cc7191a717793f69485dad2923cd34f6d48de -re8b38c279ab010c360bd6589c8600e9cf387b11f
--- Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/TreeNodeInfos/PipingFailureMechanismTreeNodeInfoTest.cs	(.../PipingFailureMechanismTreeNodeInfoTest.cs)	(revision f98cc7191a717793f69485dad2923cd34f6d48de)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/TreeNodeInfos/PipingFailureMechanismTreeNodeInfoTest.cs	(.../PipingFailureMechanismTreeNodeInfoTest.cs)	(revision e8b38c279ab010c360bd6589c8600e9cf387b11f)
@@ -174,11 +174,14 @@
 
             ContextMenuStrip contextMenuAdapter = info.ContextMenuStrip(dataMock, null, treeViewControl);
 
+            string messageBoxTitle = null, messageBoxText = null;
             DialogBoxHandler = (name, wnd) =>
             {
                 var messageBox = new MessageBoxTester(wnd);
-                Assert.AreEqual("Weet u zeker dat u alle uitvoer wilt wissen?", messageBox.Text);
-                Assert.AreEqual("Bevestigen", messageBox.Title);
+
+                messageBoxText = messageBox.Text;
+                messageBoxTitle = messageBox.Title;
+
                 if (confirm)
                 {
                     messageBox.ClickOk();
@@ -195,6 +198,8 @@
             // Then
             Assert.AreNotEqual(confirm, dataMock.CalculationsGroup.HasOutput);
 
+            Assert.AreEqual("Bevestigen", messageBoxTitle);
+            Assert.AreEqual("Weet u zeker dat u alle uitvoer wilt wissen?", messageBoxText);
             mocks.VerifyAll();
         }
 
@@ -534,12 +539,15 @@
 
             mocks.ReplayAll();
 
-            DialogBoxHandler = (name, wnd) => { };
-
             plugin.Gui = gui;
 
             var contextMenu = info.ContextMenuStrip(failureMechanism, null, treeViewControl);
 
+            DialogBoxHandler = (name, wnd) =>
+            {
+                // Don't care about dialogs in this test.
+            };
+
             // Call
             contextMenu.Items[contextMenuCalculateAllIndex].PerformClick();