Index: Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/MacroStabilityInwardsFailureMechanismSectionResultDetailedAssessmentExtensions.cs
===================================================================
diff -u -r739752c5cc7ed800dacf74e12221c227183ddc6f -rd8d1d5d4a3eabd84c2d6e07eedb75fa200c2d54e
--- Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/MacroStabilityInwardsFailureMechanismSectionResultDetailedAssessmentExtensions.cs	(.../MacroStabilityInwardsFailureMechanismSectionResultDetailedAssessmentExtensions.cs)	(revision 739752c5cc7ed800dacf74e12221c227183ddc6f)
+++ Ringtoets/MacroStabilityInwards/src/Ringtoets.MacroStabilityInwards.Data/MacroStabilityInwardsFailureMechanismSectionResultDetailedAssessmentExtensions.cs	(.../MacroStabilityInwardsFailureMechanismSectionResultDetailedAssessmentExtensions.cs)	(revision d8d1d5d4a3eabd84c2d6e07eedb75fa200c2d54e)
@@ -98,52 +98,90 @@
         }
 
         /// <summary>
-        /// Gets the contribution of all relevant <see cref="GetCalculationScenarios"/> together.
+        /// Gets the total contribution of all relevant calculation scenarios.
         /// </summary>
-        /// <param name="macroStabilityInwardsFailureMechanismSectionResult">The result to get the result for.</param>
-        /// <param name="calculations">All calculations in the failure mechanism.</param>
-        public static RoundedDouble GetTotalContribution(this MacroStabilityInwardsFailureMechanismSectionResult macroStabilityInwardsFailureMechanismSectionResult,
-                                                         IEnumerable<MacroStabilityInwardsCalculationScenario> calculations)
+        /// <param name="sectionResult">The section result to get the total contribution for.</param>
+        /// <param name="calculationScenarios">The calculation scenarios to get the total contribution for.</param>
+        /// <returns>The total contribution of all relevant calculation scenarios.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when any parameter is <c>null</c>.</exception>
+        public static RoundedDouble GetTotalContribution(this MacroStabilityInwardsFailureMechanismSectionResult sectionResult,
+                                                         IEnumerable<MacroStabilityInwardsCalculationScenario> calculationScenarios)
         {
-            return (RoundedDouble) macroStabilityInwardsFailureMechanismSectionResult
-                                   .GetCalculationScenarios(calculations)
+            if (sectionResult == null)
+            {
+                throw new ArgumentNullException(nameof(sectionResult));
+            }
+
+            if (calculationScenarios == null)
+            {
+                throw new ArgumentNullException(nameof(calculationScenarios));
+            }
+
+            return (RoundedDouble) sectionResult
+                                   .GetCalculationScenarios(calculationScenarios)
                                    .Aggregate<ICalculationScenario, double>(0, (current, calculationScenario) => current + calculationScenario.Contribution);
         }
 
         /// <summary>
-        /// Gets a list of the relevant <see cref="ICalculationScenario"/>.
+        /// Gets a collection of the relevant <see cref="MacroStabilityInwardsCalculationScenario"/>.
         /// </summary>
-        /// <param name="macroStabilityInwardsFailureMechanismSectionResult">The result to get the result for.</param>
-        /// <param name="calculations">All calculations in the failure mechanism.</param>
-        public static IEnumerable<MacroStabilityInwardsCalculationScenario> GetCalculationScenarios(this MacroStabilityInwardsFailureMechanismSectionResult macroStabilityInwardsFailureMechanismSectionResult,
-                                                                                                    IEnumerable<MacroStabilityInwardsCalculationScenario> calculations)
+        /// <param name="sectionResult">The section result to get the relevant scenarios for.</param>
+        /// <param name="calculationScenarios">The calculation scenarios to get the relevant scenarios from.</param>
+        /// <returns>A collection of relevant calculation scenarios.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when any parameter is <c>null</c>.</exception>
+        public static IEnumerable<MacroStabilityInwardsCalculationScenario> GetCalculationScenarios(
+            this MacroStabilityInwardsFailureMechanismSectionResult sectionResult,
+            IEnumerable<MacroStabilityInwardsCalculationScenario> calculationScenarios)
         {
-            IEnumerable<Segment2D> lineSegments = Math2D.ConvertLinePointsToLineSegments(macroStabilityInwardsFailureMechanismSectionResult.Section.Points);
+            if (sectionResult == null)
+            {
+                throw new ArgumentNullException(nameof(sectionResult));
+            }
 
-            return calculations
+            if (calculationScenarios == null)
+            {
+                throw new ArgumentNullException(nameof(calculationScenarios));
+            }
+
+            IEnumerable<Segment2D> lineSegments = Math2D.ConvertLinePointsToLineSegments(sectionResult.Section.Points);
+
+            return calculationScenarios
                 .Where(pc => pc.IsRelevant && pc.IsSurfaceLineIntersectionWithReferenceLineInSection(lineSegments));
         }
 
         /// <summary>
         /// Gets the status of the section result depending on the relevant calculation scenarios.
         /// </summary>
-        /// <param name="macroStabilityInwardsFailureMechanismSectionResult">The result to get the result for.</param>
-        /// <param name="calculations">All calculations in the failure mechanism.</param>
+        /// <param name="sectionResult">The section result to get the calculation status for.</param>
+        /// <param name="calculationScenarios">The calculation scenarios to get the calculation status for.</param>
+        /// <returns>The calculation scenario status for the section result.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when any parameter is <c>null</c>.</exception>
         /// <exception cref="InvalidEnumArgumentException">Thrown when any of the relevant calculations 
-        /// in <paramref name="macroStabilityInwardsFailureMechanismSectionResult"/> has an invalid <see cref="CalculationScenarioStatus"/>.</exception>
-        /// <exception cref="NotSupportedException">Thrown when any of the relevant scenarios has an unsupported value of <see cref="CalculationScenarioStatus"/>.</exception>
+        /// in <paramref name="sectionResult"/> has an invalid <see cref="CalculationScenarioStatus"/>.</exception>
+        /// <exception cref="NotSupportedException">Thrown when any of the relevant scenarios has an unsupported
+        /// value of <see cref="CalculationScenarioStatus"/>.</exception>
         public static CalculationScenarioStatus GetCalculationScenarioStatus(
-            this MacroStabilityInwardsFailureMechanismSectionResult macroStabilityInwardsFailureMechanismSectionResult,
-            IEnumerable<MacroStabilityInwardsCalculationScenario> calculations)
+            this MacroStabilityInwardsFailureMechanismSectionResult sectionResult,
+            IEnumerable<MacroStabilityInwardsCalculationScenario> calculationScenarios)
         {
+            if (sectionResult == null)
+            {
+                throw new ArgumentNullException(nameof(sectionResult));
+            }
+
+            if (calculationScenarios == null)
+            {
+                throw new ArgumentNullException(nameof(calculationScenarios));
+            }
+
             var failed = false;
             var notCalculated = false;
-            foreach (MacroStabilityInwardsCalculationScenario calculationScenario in macroStabilityInwardsFailureMechanismSectionResult.GetCalculationScenarios(calculations).Where(cs => cs.IsRelevant))
+            foreach (MacroStabilityInwardsCalculationScenario calculationScenario in sectionResult.GetCalculationScenarios(calculationScenarios).Where(cs => cs.IsRelevant))
             {
                 CalculationScenarioStatus calculationScenarioStatus = calculationScenario.Status;
                 if (!Enum.IsDefined(typeof(CalculationScenarioStatus), calculationScenarioStatus))
                 {
-                    throw new InvalidEnumArgumentException(nameof(macroStabilityInwardsFailureMechanismSectionResult),
+                    throw new InvalidEnumArgumentException(nameof(sectionResult),
                                                            (int) calculationScenarioStatus,
                                                            typeof(CalculationScenarioStatus));
                 }