Index: src/Plugins/Wti/Wti.Data/WtiProject.cs
===================================================================
diff -u -r5f7007ed48dccd78b0a07db987bf234a6705ec9b -r97ebda114265b9ccdc6cf73bab8312e5422e3de4
--- src/Plugins/Wti/Wti.Data/WtiProject.cs	(.../WtiProject.cs)	(revision 5f7007ed48dccd78b0a07db987bf234a6705ec9b)
+++ src/Plugins/Wti/Wti.Data/WtiProject.cs	(.../WtiProject.cs)	(revision 97ebda114265b9ccdc6cf73bab8312e5422e3de4)
@@ -45,6 +45,15 @@
             PipingFailureMechanism = new PipingFailureMechanism();
         }
 
+        /// <summary>
+        /// Determines whether a new <see cref="PipingFailureMechanism"/> can be added to the <see cref="WtiProject"/>.
+        /// </summary>
+        /// <returns>True if a new <see cref="PipingFailureMechanism"/> can be assigned. False otherwise.</returns>
+        public bool CanAddPipingFailureMechanism()
+        {
+            return PipingFailureMechanism == null;
+        }
+
         #region IObservable
 
         public void Attach(IObserver observer)
Index: src/Plugins/Wti/Wti.Forms/NodePresenters/WtiProjectNodePresenter.cs
===================================================================
diff -u -r493a740c5f9592074c117c718b2f9b0af310c355 -r97ebda114265b9ccdc6cf73bab8312e5422e3de4
--- src/Plugins/Wti/Wti.Forms/NodePresenters/WtiProjectNodePresenter.cs	(.../WtiProjectNodePresenter.cs)	(revision 493a740c5f9592074c117c718b2f9b0af310c355)
+++ src/Plugins/Wti/Wti.Forms/NodePresenters/WtiProjectNodePresenter.cs	(.../WtiProjectNodePresenter.cs)	(revision 97ebda114265b9ccdc6cf73bab8312e5422e3de4)
@@ -35,7 +35,7 @@
 
         public IEnumerable GetChildNodeObjects(object parentNodeData, ITreeNode node)
         {
-            var wtiProject = (WtiProject)parentNodeData;
+            var wtiProject = (WtiProject) parentNodeData;
             if (wtiProject.PipingFailureMechanism != null)
             {
                 yield return wtiProject.PipingFailureMechanism;
@@ -87,7 +87,9 @@
             var addPipingFailureMechanismItem = contextMenu.Items.Add(Resources.AddPipingFailureMechanismContextMenuItem);
             var contextMenuAdapter = new MenuItemContextMenuStripAdapter(contextMenu);
 
-            if (CanAddPipingFailureMechanism(nodeData))
+            var wtiProject = (WtiProject) nodeData;
+
+            if (wtiProject.CanAddPipingFailureMechanism())
             {
                 addPipingFailureMechanismItem.Tag = nodeData;
                 addPipingFailureMechanismItem.Click += InitializePipingFailureMechanismForWtiProject;
@@ -102,23 +104,6 @@
             return contextMenuAdapter;
         }
 
-        private bool CanAddPipingFailureMechanism(object nodeData)
-        {
-            var wtiProject = nodeData as WtiProject;
-            return wtiProject != null && wtiProject.PipingFailureMechanism == null;
-        }
-
-        private void InitializePipingFailureMechanismForWtiProject(object sender, EventArgs e)
-        {
-            var treeNode = (ToolStripItem) sender;
-            if (treeNode != null)
-            {
-                var wtiProject = (WtiProject) treeNode.Tag;
-                wtiProject.InitializePipingFailureMechanism();
-                wtiProject.NotifyObservers();
-            }
-        }
-
         public void OnPropertyChanged(object sender, ITreeNode node, PropertyChangedEventArgs e) {}
 
         public void OnCollectionChanged(object sender, NotifyCollectionChangingEventArgs e) {}
@@ -138,5 +123,16 @@
 
             return true;
         }
+
+        private void InitializePipingFailureMechanismForWtiProject(object sender, EventArgs e)
+        {
+            var treeNode = (ToolStripItem) sender;
+            if (treeNode != null)
+            {
+                var wtiProject = (WtiProject) treeNode.Tag;
+                wtiProject.InitializePipingFailureMechanism();
+                wtiProject.NotifyObservers();
+            }
+        }
     }
 }
\ No newline at end of file
Index: test/Common/DelftTools.Tests/Controls/Swf/Table/TableViewTest.cs
===================================================================
diff -u -r0a2e4c7ac0cdcaf0038721c74ed9c823f1e14f91 -r97ebda114265b9ccdc6cf73bab8312e5422e3de4
--- test/Common/DelftTools.Tests/Controls/Swf/Table/TableViewTest.cs	(.../TableViewTest.cs)	(revision 0a2e4c7ac0cdcaf0038721c74ed9c823f1e14f91)
+++ test/Common/DelftTools.Tests/Controls/Swf/Table/TableViewTest.cs	(.../TableViewTest.cs)	(revision 97ebda114265b9ccdc6cf73bab8312e5422e3de4)
@@ -872,7 +872,7 @@
                 var dxColumn = tableView.Columns[1].FieldValue<GridColumn>("dxColumn");
                 var dxEditor = (RepositoryItemLookUpEdit) dxColumn.ColumnEdit;
                 var list = dxEditor.DataSource as IEnumerable;
-                Assert.NotNull(list);
+                Assert.IsNotNull(list);
                 TypeUtils.GetPropertyValue(list.OfType<object>().First(), "DisplayText").Should().Be.EqualTo("[item type1]"); // Only have formatting in ComboBox
                 tableView.GetCellDisplayText(0, 1).Should().Be.EqualTo("item type1"); // No formatting should be visible in TableView
             });
@@ -1890,8 +1890,8 @@
                 Data = list
             };
 
-            Assert.Null(tableView.GetRowObjectAt(-1));
-            Assert.Null(tableView.GetRowObjectAt(10));
+            Assert.IsNull(tableView.GetRowObjectAt(-1));
+            Assert.IsNull(tableView.GetRowObjectAt(10));
         }
 
         [Test]
Index: test/Common/DelftTools.Utils.Tests/PropertyBag/DynamicPropertyBagTest.cs
===================================================================
diff -u -rfbe5d1ac043ae74461b82b0ab71c5388bfbbc58b -r97ebda114265b9ccdc6cf73bab8312e5422e3de4
--- test/Common/DelftTools.Utils.Tests/PropertyBag/DynamicPropertyBagTest.cs	(.../DynamicPropertyBagTest.cs)	(revision fbe5d1ac043ae74461b82b0ab71c5388bfbbc58b)
+++ test/Common/DelftTools.Utils.Tests/PropertyBag/DynamicPropertyBagTest.cs	(.../DynamicPropertyBagTest.cs)	(revision 97ebda114265b9ccdc6cf73bab8312e5422e3de4)
@@ -119,7 +119,7 @@
             });
 
             namePropertyDescriptor = propertyDescriptorCollection.Find("Name", false);
-            Assert.Null(namePropertyDescriptor, "Name should not be visible anymore");
+            Assert.IsNull(namePropertyDescriptor, "Name should not be visible anymore");
         }
 
         [Test]
Index: test/Common/SharpMap.UI.Tests/Tools/SelectToolTest.cs
===================================================================
diff -u -r358c79275eb3606f034919380d07b169cc1d41c0 -r97ebda114265b9ccdc6cf73bab8312e5422e3de4
--- test/Common/SharpMap.UI.Tests/Tools/SelectToolTest.cs	(.../SelectToolTest.cs)	(revision 358c79275eb3606f034919380d07b169cc1d41c0)
+++ test/Common/SharpMap.UI.Tests/Tools/SelectToolTest.cs	(.../SelectToolTest.cs)	(revision 97ebda114265b9ccdc6cf73bab8312e5422e3de4)
@@ -196,7 +196,7 @@
             var items = mapControl.SelectTool.GetContextMenuItems(new Coordinate(4, 4));
 
             var mapToolContextMenuItem = items.FirstOrDefault();
-            Assert.NotNull(mapToolContextMenuItem);
+            Assert.IsNotNull(mapToolContextMenuItem);
             Assert.IsInstanceOf<ToolStripMenuItem>(mapToolContextMenuItem.MenuItem);
 
             var dropDownItems = mapToolContextMenuItem.MenuItem.DropDownItems;
@@ -207,7 +207,7 @@
             items = mapControl.SelectTool.GetContextMenuItems(new Coordinate(4, 4));
 
             mapToolContextMenuItem = items.FirstOrDefault();
-            Assert.NotNull(mapToolContextMenuItem);
+            Assert.IsNotNull(mapToolContextMenuItem);
             Assert.IsInstanceOf<ToolStripMenuItem>(mapToolContextMenuItem.MenuItem);
 
             dropDownItems = mapToolContextMenuItem.MenuItem.DropDownItems;
Index: test/DeltaShell/DeltaShell.Plugins.SharpMapGis.Tests/BackGroundMapLayerTest.cs
===================================================================
diff -u -r5fc71a385897af92ccb092f2f969b5709afab85a -r97ebda114265b9ccdc6cf73bab8312e5422e3de4
--- test/DeltaShell/DeltaShell.Plugins.SharpMapGis.Tests/BackGroundMapLayerTest.cs	(.../BackGroundMapLayerTest.cs)	(revision 5fc71a385897af92ccb092f2f969b5709afab85a)
+++ test/DeltaShell/DeltaShell.Plugins.SharpMapGis.Tests/BackGroundMapLayerTest.cs	(.../BackGroundMapLayerTest.cs)	(revision 97ebda114265b9ccdc6cf73bab8312e5422e3de4)
@@ -72,7 +72,7 @@
 
             var clonedBackgroundLayer = backgroundLayer.Clone() as BackGroundMapLayer;
 
-            Assert.NotNull(clonedBackgroundLayer);
+            Assert.IsNotNull(clonedBackgroundLayer);
             Assert.AreEqual(backgroundLayer.Name, clonedBackgroundLayer.Name);
             Assert.AreEqual(backgroundLayer.Layers.Count, clonedBackgroundLayer.Layers.Count);
             Assert.AreEqual(backgroundLayer.Layers[0].Name, clonedBackgroundLayer.Layers[0].Name);
Index: test/Plugins/Wti/Wti.Calculation.Test/Piping/PipingCalculationTest.cs
===================================================================
diff -u -ra3b93c36c2051bd6112327bff0d836ae7883737d -r97ebda114265b9ccdc6cf73bab8312e5422e3de4
--- test/Plugins/Wti/Wti.Calculation.Test/Piping/PipingCalculationTest.cs	(.../PipingCalculationTest.cs)	(revision a3b93c36c2051bd6112327bff0d836ae7883737d)
+++ test/Plugins/Wti/Wti.Calculation.Test/Piping/PipingCalculationTest.cs	(.../PipingCalculationTest.cs)	(revision 97ebda114265b9ccdc6cf73bab8312e5422e3de4)
@@ -15,7 +15,7 @@
 
             PipingCalculationResult actual = new PipingCalculation(input).Calculate();
 
-            Assert.NotNull(actual);
+            Assert.IsNotNull(actual);
             Assert.IsFalse(double.IsNaN(actual.UpliftZValue));
             Assert.IsFalse(double.IsNaN(actual.UpliftFactorOfSafety));
             Assert.IsFalse(double.IsNaN(actual.HeaveZValue));
Index: test/Plugins/Wti/Wti.Data.Test/WtiProjectTest.cs
===================================================================
diff -u -r5f7007ed48dccd78b0a07db987bf234a6705ec9b -r97ebda114265b9ccdc6cf73bab8312e5422e3de4
--- test/Plugins/Wti/Wti.Data.Test/WtiProjectTest.cs	(.../WtiProjectTest.cs)	(revision 5f7007ed48dccd78b0a07db987bf234a6705ec9b)
+++ test/Plugins/Wti/Wti.Data.Test/WtiProjectTest.cs	(.../WtiProjectTest.cs)	(revision 97ebda114265b9ccdc6cf73bab8312e5422e3de4)
@@ -30,7 +30,7 @@
             project.InitializePipingFailureMechanism();
 
             // Assert
-            Assert.NotNull(project.PipingFailureMechanism);
+            Assert.IsNotNull(project.PipingFailureMechanism);
 
         }
 
@@ -43,7 +43,7 @@
             PipingFailureMechanism notExpectedFailureMechanism = project.PipingFailureMechanism;
 
             // Precondition
-            Assert.NotNull(notExpectedFailureMechanism);
+            Assert.IsNotNull(notExpectedFailureMechanism);
 
             // Call
             project.InitializePipingFailureMechanism();
@@ -61,7 +61,7 @@
             PipingFailureMechanism notExpectedFailureMechanism = project.PipingFailureMechanism;
 
             // Precondition
-            Assert.NotNull(notExpectedFailureMechanism);
+            Assert.IsNotNull(notExpectedFailureMechanism);
 
             // Call
             project.ClearPipingFailureMechanism();
@@ -77,7 +77,7 @@
             var project = new WtiProject();
 
             // Precondition
-            Assert.Null(project.PipingFailureMechanism);
+            Assert.IsNull(project.PipingFailureMechanism);
 
             // Call
             project.ClearPipingFailureMechanism();
@@ -123,5 +123,32 @@
             // Assert
             mocks.VerifyAll(); // Expect no calls on observer
         }
+
+        [Test]
+        public void CanAddPipingFailureMechanism_NoPipingFailureMechanismAssigned_ReturnsTrue()
+        {
+            // Setup
+            var project = new WtiProject();
+
+            // Call
+            var result = project.CanAddPipingFailureMechanism();
+
+            // Assert
+            Assert.IsTrue(result);
+        }
+
+        [Test]
+        public void CanAddPipingFailureMechanism_PipingFailureMechanismInitialized_ReturnsTrue()
+        {
+            // Setup
+            var project = new WtiProject();
+            project.InitializePipingFailureMechanism();
+
+            // Call
+            var result = project.CanAddPipingFailureMechanism();
+
+            // Assert
+            Assert.IsFalse(result);
+        }
     }
 }
\ No newline at end of file
Index: test/Plugins/Wti/Wti.Forms.Test/NodePresenters/PipingDataNodePresenterTest.cs
===================================================================
diff -u -r5f7007ed48dccd78b0a07db987bf234a6705ec9b -r97ebda114265b9ccdc6cf73bab8312e5422e3de4
--- test/Plugins/Wti/Wti.Forms.Test/NodePresenters/PipingDataNodePresenterTest.cs	(.../PipingDataNodePresenterTest.cs)	(revision 5f7007ed48dccd78b0a07db987bf234a6705ec9b)
+++ test/Plugins/Wti/Wti.Forms.Test/NodePresenters/PipingDataNodePresenterTest.cs	(.../PipingDataNodePresenterTest.cs)	(revision 97ebda114265b9ccdc6cf73bab8312e5422e3de4)
@@ -291,7 +291,7 @@
             var contextMenu = nodePresenter.GetContextMenu(nodeMock, dataMock) as MenuItemContextMenuStripAdapter;
 
             // Assert
-            Assert.NotNull(contextMenu);
+            Assert.IsNotNull(contextMenu);
             Assert.AreEqual(2, contextMenu.ContextMenuStrip.Items.Count);
             Assert.AreEqual(WtiFormsResources.PipingDataContextMenuCalculate, contextMenu.ContextMenuStrip.Items[1].Text);
             Assert.AreEqual(WtiFormsResources.PipingDataContextMenuValidate, contextMenu.ContextMenuStrip.Items[0].Text);
Index: test/Plugins/Wti/Wti.Forms.Test/NodePresenters/PipingFailureMechanismNodePresenterTest.cs
===================================================================
diff -u -r5f7007ed48dccd78b0a07db987bf234a6705ec9b -r97ebda114265b9ccdc6cf73bab8312e5422e3de4
--- test/Plugins/Wti/Wti.Forms.Test/NodePresenters/PipingFailureMechanismNodePresenterTest.cs	(.../PipingFailureMechanismNodePresenterTest.cs)	(revision 5f7007ed48dccd78b0a07db987bf234a6705ec9b)
+++ test/Plugins/Wti/Wti.Forms.Test/NodePresenters/PipingFailureMechanismNodePresenterTest.cs	(.../PipingFailureMechanismNodePresenterTest.cs)	(revision 97ebda114265b9ccdc6cf73bab8312e5422e3de4)
@@ -253,7 +253,7 @@
             var contextMenu = nodePresenter.GetContextMenu(nodeMock, dataMock);
 
             // Assert
-            Assert.Null(contextMenu);
+            Assert.IsNull(contextMenu);
             mocks.VerifyAll(); // Expect no calls on arguments
         }
 
Index: test/Plugins/Wti/Wti.Forms.Test/NodePresenters/WtiProjectNodePresenterTest.cs
===================================================================
diff -u -r493a740c5f9592074c117c718b2f9b0af310c355 -r97ebda114265b9ccdc6cf73bab8312e5422e3de4
--- test/Plugins/Wti/Wti.Forms.Test/NodePresenters/WtiProjectNodePresenterTest.cs	(.../WtiProjectNodePresenterTest.cs)	(revision 493a740c5f9592074c117c718b2f9b0af310c355)
+++ test/Plugins/Wti/Wti.Forms.Test/NodePresenters/WtiProjectNodePresenterTest.cs	(.../WtiProjectNodePresenterTest.cs)	(revision 97ebda114265b9ccdc6cf73bab8312e5422e3de4)
@@ -280,7 +280,7 @@
             var contextMenu = nodePresenter.GetContextMenu(nodeMock, wtiProject) as MenuItemContextMenuStripAdapter;
 
             // Assert
-            Assert.NotNull(contextMenu);
+            Assert.IsNotNull(contextMenu);
             Assert.AreEqual(1, contextMenu.ContextMenuStrip.Items.Count);
             Assert.AreEqual(WtiFormsResources.AddPipingFailureMechanismContextMenuItem, contextMenu.ContextMenuStrip.Items[0].Text);
             Assert.AreEqual(WtiFormsResources.WtiProjectTooltipAddPipingFailureMechanism, contextMenu.ContextMenuStrip.Items[0].ToolTipText);
@@ -305,7 +305,7 @@
             var contextMenu = nodePresenter.GetContextMenu(nodeMock, wtiProject) as MenuItemContextMenuStripAdapter;
 
             // Assert
-            Assert.NotNull(contextMenu);
+            Assert.IsNotNull(contextMenu);
             Assert.AreEqual(1, contextMenu.ContextMenuStrip.Items.Count);
             Assert.AreEqual(WtiFormsResources.AddPipingFailureMechanismContextMenuItem, contextMenu.ContextMenuStrip.Items[0].Text);
             Assert.AreEqual(WtiFormsResources.WtiProjectTooltipPipingFailureMechanismAlreadyAdded, contextMenu.ContextMenuStrip.Items[0].ToolTipText);
@@ -411,15 +411,15 @@
             var contextMenu = nodePresenter.GetContextMenu(nodeMock, wtiProject) as MenuItemContextMenuStripAdapter;
 
             // Preconditions
-            Assert.NotNull(contextMenu);
+            Assert.IsNotNull(contextMenu);
             Assert.IsNull(wtiProject.PipingFailureMechanism);
             Assert.AreEqual(1, contextMenu.ContextMenuStrip.Items.Count);
 
             // Call
             contextMenu.ContextMenuStrip.Items[0].PerformClick();
 
             // Assert
-            Assert.NotNull(wtiProject.PipingFailureMechanism);
+            Assert.IsNotNull(wtiProject.PipingFailureMechanism);
         }
     }
 }
\ No newline at end of file
Index: test/Plugins/Wti/Wti.Service.Test/PipingCalculationServiceTest.cs
===================================================================
diff -u -r49b7320ad56bfa60788e8792b79dd537318f68ff -r97ebda114265b9ccdc6cf73bab8312e5422e3de4
--- test/Plugins/Wti/Wti.Service.Test/PipingCalculationServiceTest.cs	(.../PipingCalculationServiceTest.cs)	(revision 49b7320ad56bfa60788e8792b79dd537318f68ff)
+++ test/Plugins/Wti/Wti.Service.Test/PipingCalculationServiceTest.cs	(.../PipingCalculationServiceTest.cs)	(revision 97ebda114265b9ccdc6cf73bab8312e5422e3de4)
@@ -50,7 +50,7 @@
 
             // Assert
             Assert.AreEqual(PipingCalculationResult.Successful, result);
-            Assert.NotNull(validPipingData.Output);
+            Assert.IsNotNull(validPipingData.Output);
         }
 
         [Test]
@@ -98,7 +98,7 @@
 
             // Assert
             Assert.AreEqual(PipingCalculationResult.CalculationErrors, result);
-            Assert.Null(validPipingData.Output);
+            Assert.IsNull(validPipingData.Output);
         }
     }
 }
\ No newline at end of file