Index: Riskeer/Common/src/Riskeer.Common.Forms/Helpers/FailureMechanismAssemblyResultValidationHelper.cs
===================================================================
diff -u
--- Riskeer/Common/src/Riskeer.Common.Forms/Helpers/FailureMechanismAssemblyResultValidationHelper.cs	(revision 0)
+++ Riskeer/Common/src/Riskeer.Common.Forms/Helpers/FailureMechanismAssemblyResultValidationHelper.cs	(revision 093f75950ed3ba89603f4dfb0e9ecaac5759376c)
@@ -0,0 +1,51 @@
+// Copyright (C) Stichting Deltares 2021. All rights reserved.
+//
+// This file is part of Riskeer.
+//
+// Riskeer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+//
+// All names, logos, and references to "Deltares" are registered trademarks of
+// Stichting Deltares and remain full property of Stichting Deltares at all times.
+// All rights reserved.
+
+using System;
+using Riskeer.Common.Data.FailureMechanism;
+using Riskeer.Common.Forms.Properties;
+
+namespace Riskeer.Common.Forms.Helpers
+{
+    /// <summary>
+    /// Class containing validation helper methods for a <see cref="FailureMechanismAssemblyResult"/> 
+    /// </summary>
+    public static class FailureMechanismAssemblyResultValidationHelper
+    {
+        /// <summary>
+        /// Gets the validation error for a <see cref="FailureMechanismAssemblyResult"/>.
+        /// </summary>
+        /// <param name="result">The <see cref="FailureMechanismAssemblyResult"/> to get the validation messages for.</param>
+        /// <returns>An error message when the validation fails or <see cref="string.Empty"/> when there are no errors.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="result"/> is <c>null</c>.</exception>
+        public static string GetValidationError(FailureMechanismAssemblyResult result)
+        {
+            if (result == null)
+            {
+                throw new ArgumentNullException(nameof(result));
+            }
+
+            return result.IsManualProbability() && double.IsNaN(result.ManualFailureMechanismAssemblyProbability)
+                       ? Resources.FailureProbability_must_not_be_NaN
+                       : string.Empty;
+        }
+    }
+}
\ No newline at end of file
Fisheye: Tag 093f75950ed3ba89603f4dfb0e9ecaac5759376c refers to a dead (removed) revision in file `Riskeer/Common/src/Riskeer.Common.Forms/Helpers/FailurePathAssemblyResultValidationHelper.cs'.
Fisheye: No comparison available.  Pass `N' to diff?
Index: Riskeer/Common/src/Riskeer.Common.Forms/Views/FailureMechanismResultView.cs
===================================================================
diff -u -rba639d608bbfcd02a294acfa6c428d41f2e627ce -r093f75950ed3ba89603f4dfb0e9ecaac5759376c
--- Riskeer/Common/src/Riskeer.Common.Forms/Views/FailureMechanismResultView.cs	(.../FailureMechanismResultView.cs)	(revision ba639d608bbfcd02a294acfa6c428d41f2e627ce)
+++ Riskeer/Common/src/Riskeer.Common.Forms/Views/FailureMechanismResultView.cs	(.../FailureMechanismResultView.cs)	(revision 093f75950ed3ba89603f4dfb0e9ecaac5759376c)
@@ -370,7 +370,7 @@
             FailureMechanismAssemblyResult assemblyResult = FailureMechanism.AssemblyResult;
             if (assemblyResult.IsManualProbability())
             {
-                SetErrorMessage(FailurePathAssemblyResultValidationHelper.GetValidationError(assemblyResult));
+                SetErrorMessage(FailureMechanismAssemblyResultValidationHelper.GetValidationError(assemblyResult));
             }
         }
 
Index: Riskeer/Common/test/Riskeer.Common.Forms.Test/Helpers/FailureMechanismAssemblyResultValidationHelperTest.cs
===================================================================
diff -u
--- Riskeer/Common/test/Riskeer.Common.Forms.Test/Helpers/FailureMechanismAssemblyResultValidationHelperTest.cs	(revision 0)
+++ Riskeer/Common/test/Riskeer.Common.Forms.Test/Helpers/FailureMechanismAssemblyResultValidationHelperTest.cs	(revision 093f75950ed3ba89603f4dfb0e9ecaac5759376c)
@@ -0,0 +1,94 @@
+// Copyright (C) Stichting Deltares 2021. All rights reserved.
+//
+// This file is part of Riskeer.
+//
+// Riskeer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+//
+// All names, logos, and references to "Deltares" are registered trademarks of
+// Stichting Deltares and remain full property of Stichting Deltares at all times.
+// All rights reserved.
+
+using System;
+using NUnit.Framework;
+using Riskeer.Common.Data.FailureMechanism;
+using Riskeer.Common.Forms.Helpers;
+
+namespace Riskeer.Common.Forms.Test.Helpers
+{
+    [TestFixture]
+    public class FailureMechanismAssemblyResultValidationHelperTest
+    {
+        [Test]
+        public void GetValidationError_ResultNull_ThrowsArgumentNullException()
+        {
+            // Call
+            void Call() => FailureMechanismAssemblyResultValidationHelper.GetValidationError(null);
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(Call);
+            Assert.AreEqual("result", exception.ParamName);
+        }
+
+        [Test]
+        public void GetValidationError_WithResultManualAndInvalidProbability_ReturnsErrorMessage()
+        {
+            // Setup
+            var result = new FailureMechanismAssemblyResult
+            {
+                ProbabilityResultType = FailureMechanismAssemblyProbabilityResultType.Manual,
+                ManualFailureMechanismAssemblyProbability = double.NaN
+            };
+
+            // Call
+            string message = FailureMechanismAssemblyResultValidationHelper.GetValidationError(result);
+
+            // Assert
+            Assert.AreEqual("Er moet een waarde worden ingevuld voor de faalkans.", message);
+        }
+
+        [Test]
+        public void GetValidationError_WithResultManualAndValidProbability_ReturnsEmptyMessage()
+        {
+            // Setup
+            var random = new Random(21);
+            var result = new FailureMechanismAssemblyResult
+            {
+                ProbabilityResultType = FailureMechanismAssemblyProbabilityResultType.Manual,
+                ManualFailureMechanismAssemblyProbability = random.NextDouble()
+            };
+
+            // Call
+            string message = FailureMechanismAssemblyResultValidationHelper.GetValidationError(result);
+
+            // Assert
+            Assert.IsEmpty(message);
+        }
+
+        [Test]
+        public void GetValidationError_WithResultAutomatic_ReturnsEmptyMessage()
+        {
+            // Setup
+            var result = new FailureMechanismAssemblyResult
+            {
+                ProbabilityResultType = FailureMechanismAssemblyProbabilityResultType.Automatic
+            };
+
+            // Call
+            string message = FailureMechanismAssemblyResultValidationHelper.GetValidationError(result);
+
+            // Assert
+            Assert.IsEmpty(message);
+        }
+    }
+}
\ No newline at end of file
Fisheye: Tag 093f75950ed3ba89603f4dfb0e9ecaac5759376c refers to a dead (removed) revision in file `Riskeer/Common/test/Riskeer.Common.Forms.Test/Helpers/FailurePathAssemblyResultValidationHelperTest.cs'.
Fisheye: No comparison available.  Pass `N' to diff?
Index: Riskeer/Integration/src/Riskeer.Integration.Forms/Factories/FailureMechanismAssemblyResultRowFactory.cs
===================================================================
diff -u -rba639d608bbfcd02a294acfa6c428d41f2e627ce -r093f75950ed3ba89603f4dfb0e9ecaac5759376c
--- Riskeer/Integration/src/Riskeer.Integration.Forms/Factories/FailureMechanismAssemblyResultRowFactory.cs	(.../FailureMechanismAssemblyResultRowFactory.cs)	(revision ba639d608bbfcd02a294acfa6c428d41f2e627ce)
+++ Riskeer/Integration/src/Riskeer.Integration.Forms/Factories/FailureMechanismAssemblyResultRowFactory.cs	(.../FailureMechanismAssemblyResultRowFactory.cs)	(revision 093f75950ed3ba89603f4dfb0e9ecaac5759376c)
@@ -66,7 +66,7 @@
         {
             FailureMechanismAssemblyResult assemblyResult = failureMechanism.AssemblyResult;
 
-            string validationError = FailurePathAssemblyResultValidationHelper.GetValidationError(assemblyResult);
+            string validationError = FailureMechanismAssemblyResultValidationHelper.GetValidationError(assemblyResult);
             return !string.IsNullOrEmpty(validationError)
                        ? new FailureMechanismAssemblyResultRow(failureMechanism, validationError)
                        : new FailureMechanismAssemblyResultRow(failureMechanism, assemblyResult.ManualFailureMechanismAssemblyProbability);