Fix #89

SysML2.NET.Tests/Extend/ActionDefinitionExtensionsTestFixture.cs

@@ -21,18 +21,39 @@
 namespace SysML2.NET.Tests.Extend
 {
     using System;
-    
+
     using NUnit.Framework;
-
+
+    using SysML2.NET.Core.POCO.Core.Types;
     using SysML2.NET.Core.POCO.Systems.Actions;
+    using SysML2.NET.Core.POCO.Systems.DefinitionAndUsage;
+    using SysML2.NET.Extensions;
 
     [TestFixture]
     public class ActionDefinitionExtensionsTestFixture
     {
         [Test]
-        public void ComputeAction_ThrowsNotSupportedException()
+        public void VerifyComputeAction()
         {
-            Assert.That(() => ((IActionDefinition)null).ComputeAction(), Throws.TypeOf<NotSupportedException>());
+            Assert.That(() => ((IActionDefinition)null).ComputeAction(), Throws.TypeOf<ArgumentNullException>());
+
+            var emptyActionDefinition = new ActionDefinition();
+
+            Assert.That(emptyActionDefinition.ComputeAction(), Has.Count.EqualTo(0));
+
+            // Only ActionUsage instances must be returned; a bare Usage must be filtered out.
+            var subject = new ActionDefinition();
+            var actionUsage = new ActionUsage();
+            var bareUsage = new Usage();
+
+            subject.AssignOwnership(new FeatureMembership(), actionUsage);
+            subject.AssignOwnership(new FeatureMembership(), bareUsage);
+
+            using (Assert.EnterMultipleScope())
+            {
+                Assert.That(subject.ComputeAction(), Does.Contain(actionUsage));
+                Assert.That(subject.ComputeAction(), Does.Not.Contain(bareUsage));
+            }
         }
     }
 }

SysML2.NET/Extend/ActionDefinitionExtensions.cs

@@ -22,6 +22,7 @@ namespace SysML2.NET.Core.POCO.Systems.Actions
 {
     using System;
     using System.Collections.Generic;
+    using System.Linq;
 
     using SysML2.NET.Core.Core.Types;
     using SysML2.NET.Core.Root.Namespaces;
@@ -75,10 +76,11 @@ internal static class ActionDefinitionExtensions
         /// <returns>
         /// the computed result
         /// </returns>
-        [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
         internal static List<IActionUsage> ComputeAction(this IActionDefinition actionDefinitionSubject)
         {
-            throw new NotSupportedException("Create a GitHub issue when this method is required");
+            return actionDefinitionSubject == null
+                ? throw new ArgumentNullException(nameof(actionDefinitionSubject))
+                : [.. actionDefinitionSubject.usage.OfType<IActionUsage>()];
         }
 
     }