Provided implementation of extension method for Relationship interface

SysML2.NET.Tests/Extend/ElementExtensionsTestFixture.cs

@@ -70,7 +70,7 @@ public void VerifyComputeIsLibraryElement()
             using (Assert.EnterMultipleScope())
             {
                 Assert.That(element.ComputeIsLibraryElement, Is.False);
-                Assert.That(documentation.ComputeIsLibraryElement, Throws.TypeOf<NotSupportedException>());
+                Assert.That(documentation.ComputeIsLibraryElement, Is.False);
             }
         }
 
@@ -289,7 +289,17 @@ public void VerifyComputePathOperation()
             using (Assert.EnterMultipleScope())
             {
                 Assert.That(element.ComputePathOperation, Is.EqualTo("name"));
-                Assert.That(secondElement.ComputePathOperation, Throws.TypeOf<NotSupportedException>());
+                Assert.That(secondElement.ComputePathOperation, Is.EqualTo("/2/1"));
+            }
+
+            namespaceElement.DeclaredName = "namespace";
+            membership.DeclaredName = "firstMember";
+            secondMembership.DeclaredName = "secondMember";
+
+            using (Assert.EnterMultipleScope())
+            {
+                Assert.That(element.ComputePathOperation, Is.EqualTo("name"));
+                Assert.That(secondElement.ComputePathOperation, Is.EqualTo("/2/1"));
             }
         }
 

SysML2.NET.Tests/Extend/RelationshipExtensionsTestFixture.cs

@@ -21,18 +21,61 @@
 namespace SysML2.NET.Tests.Extend
 {
     using System;
-
+
+    using Moq;
+
     using NUnit.Framework;
 
     using SysML2.NET.Core.POCO.Root.Elements;
+    using SysML2.NET.Core.POCO.Root.Namespaces;
+    using SysML2.NET.Core.POCO.Systems.DefinitionAndUsage;
 
     [TestFixture]
     public class RelationshipExtensionsTestFixture
     {
         [Test]
-        public void ComputeRelatedElement_ThrowsNotSupportedException()
+        public void VerfiyComputeRelatedElement()
+        {
+            Assert.That(() => ((IRelationship)null).ComputeRelatedElement(), Throws.TypeOf<ArgumentNullException>());
+
+            var relationship = new Mock<IRelationship>();
+            relationship.Setup(x => x.Source).Returns([]);
+            relationship.Setup(x => x.Target).Returns([]);
+
+            Assert.That(relationship.Object.ComputeRelatedElement(), Is.Empty);
+
+            var sourceDefinition = new Definition();
+            relationship.Setup(x => x.Source).Returns([sourceDefinition]);
+
+            Assert.That(relationship.Object.ComputeRelatedElement(), Is.EquivalentTo([sourceDefinition]));
+
+            var targetDefinition = new Definition();
+            relationship.Setup(x => x.Target).Returns([targetDefinition]);
+
+            Assert.That(relationship.Object.ComputeRelatedElement(), Is.EquivalentTo([sourceDefinition,  targetDefinition]));
+            var secondSource = new Definition();
+
+            relationship.Setup(x => x.Source).Returns([sourceDefinition, secondSource]);
+            Assert.That(relationship.Object.ComputeRelatedElement(), Is.EquivalentTo([sourceDefinition, secondSource, targetDefinition]));
+        }
+
+        [Test]
+        public void VerifyComputeRedefinedLibraryNamespaceOperation()
+        {
+            Assert.That(() => ((IRelationship)null).ComputeRedefinedLibraryNamespaceOperation(), Throws.TypeOf<ArgumentNullException>());
+        }
+
+        [Test]
+        public void VerifyComputeRedefinedPathOperation()
         {
-            Assert.That(() => ((IRelationship)null).ComputeRelatedElement(), Throws.TypeOf<NotSupportedException>());
+            Assert.That(() => ((IRelationship)null).ComputeRedefinedPathOperation(), Throws.TypeOf<ArgumentNullException>());
+
+            var membership = new OwningMembership()
+            {
+                DeclaredName = "name"
+            };
+
+            Assert.That(((IRelationship)membership).ComputeRedefinedPathOperation(), Is.Empty);
         }
     }
 }

SysML2.NET.Tests/SysML2.NET.Tests.csproj

@@ -20,6 +20,7 @@
     <ItemGroup>
         <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="10.0.5" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.4.0" />
+        <PackageReference Include="Moq" Version="4.20.72" />
         <PackageReference Include="NUnit" Version="4.5.1" />
         <PackageReference Include="NUnit.Console" Version="3.22.0" />
         <PackageReference Include="NUnit3TestAdapter" Version="6.2.0" />

SysML2.NET/Extend/RelationshipExtensions.cs

@@ -22,6 +22,7 @@ namespace SysML2.NET.Core.POCO.Root.Elements
 {
     using System;
     using System.Collections.Generic;
+    using System.Linq;
 
     using SysML2.NET.Core.POCO.Root.Annotations;
     using SysML2.NET.Core.POCO.Root.Namespaces;
@@ -41,10 +42,9 @@ internal static class RelationshipExtensions
         /// <returns>
         /// the computed result
         /// </returns>
-        [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
         internal static List<IElement> ComputeRelatedElement(this IRelationship relationshipSubject)
         {
-            throw new NotSupportedException("Create a GitHub issue when this method is required");
+            return relationshipSubject == null ? throw new ArgumentNullException(nameof(relationshipSubject)) : [..relationshipSubject.Source, ..relationshipSubject.Target];
         }
 
         /// <summary>
@@ -57,10 +57,14 @@ internal static List<IElement> ComputeRelatedElement(this IRelationship relation
         /// <returns>
         /// The expected <see cref="INamespace" />
         /// </returns>
-        [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
         internal static INamespace ComputeRedefinedLibraryNamespaceOperation(this IRelationship relationshipSubject)
         {
-            throw new NotSupportedException("Create a GitHub issue when this method is required");
+            if (relationshipSubject == null)
+            {
+                throw new ArgumentNullException(nameof(relationshipSubject));
+            }
+
+            return relationshipSubject.OwningRelatedElement?.LibraryNamespace() ?? relationshipSubject.OwningRelationship?.LibraryNamespace();
         }
 
         /// <summary>
@@ -75,10 +79,20 @@ internal static INamespace ComputeRedefinedLibraryNamespaceOperation(this IRelat
         /// <returns>
         /// The expected <see cref="string" />
         /// </returns>
-        [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
         internal static string ComputeRedefinedPathOperation(this IRelationship relationshipSubject)
         {
-            throw new NotSupportedException("Create a GitHub issue when this method is required");
+            if (relationshipSubject == null)
+            {
+                throw new ArgumentNullException(nameof(relationshipSubject));
+            }
+
+            if (relationshipSubject.OwningRelationship == null && relationshipSubject.OwningRelatedElement != null)
+            {
+                var index = ((IContainedElement)relationshipSubject.OwningRelatedElement).OwnedRelationship.IndexOf(relationshipSubject) + 1;
+                return $"{relationshipSubject.OwningRelatedElement.Path()}/{index}";
+            }
+
+            return relationshipSubject.ComputePathOperation();
         }
     }
 }