Merge pull request #57 from TestCentric/issue-55

Throw ExtensibilityException when an extension constructor throws and exception

Author: CharliePoole

GitVersion.yml

@@ -1,4 +1,4 @@
-next-version: 3.0.3
+next-version: 3.2.0
 mode: ContinuousDelivery
 legacy-semver-padding: 5
 build-metadata-padding: 5

src/testcentric.extensibility.fakes/FakeExtensions.cs

@@ -95,6 +95,20 @@ public void WriteResultFile(XmlNode resultNode, TextWriter writer)
             throw new NotImplementedException();
         }
     }
+
+    [Extension(Enabled = false)]
+    public class FakeExtension_ThrowsInConstructor : ITestEventListener
+    {
+        public FakeExtension_ThrowsInConstructor()
+        {
+            throw new NotImplementedException();
+        }
+
+        public void OnTestEvent(string text)
+        {
+            throw new System.NotImplementedException();
+        }
+    }
 }
 
 namespace NUnit.Engine.Extensibility

src/testcentric.extensibility.tests/ExtensionManagerTests.cs

@@ -143,6 +143,7 @@ internal class ThisIsNotAnExtensionPoint
         [
             "TestCentric.Engine.Extensibility.FakeAgentLauncher",
             "TestCentric.Engine.Extensibility.FakeTestEventListener",
+            "TestCentric.Engine.Extensibility.FakeExtension_ThrowsInConstructor",
             "NUnit.Engine.Extensibility.FakeProjectLoader"
         ];
 
@@ -171,6 +172,18 @@ public void DisabledExtensionMayBeEnabled()
                    .And.Property(nameof(ExtensionNode.Enabled)).True);
         }
 
+        [Test]
+        public void ExtensionThrowsInConstructor()
+        {
+            string typeName = "TestCentric.Engine.Extensibility.FakeExtension_ThrowsInConstructor";
+            var iexNode = ExtensionManager.Extensions.Where(n => n.TypeName == typeName).Single();
+            var exNode = iexNode as ExtensionNode;
+
+            // Demonstrates that the exception is caused when ExtensionObject is accessed
+            var tiex = Assert.Throws<ExtensibilityException>(() => { var o = exNode.ExtensionObject; });
+            Assert.That(tiex.InnerException, Is.InstanceOf<NotImplementedException>());
+        }
+
 #if NETCOREAPP
         [TestCase("netstandard2.0", ExpectedResult = true)]
         [TestCase("net462", ExpectedResult = false)]

src/testcentric.extensibility/ExtensionNode.cs

@@ -121,14 +121,23 @@ public object ExtensionObject
         /// </summary>
         public object CreateExtensionObject(params object[] args)
         {
+            try
+            {
 #if NETFRAMEWORK
             return AppDomain.CurrentDomain.CreateInstanceFromAndUnwrap(
                 AssemblyPath, TypeName, false, 0, null, args, null, null, null);
 #else
-            var assembly = Assembly.LoadFrom(AssemblyPath);
-            var type = assembly.GetType(TypeName, throwOnError: true)!;
-            return Activator.CreateInstance(type, args)!;
+                var assembly = Assembly.LoadFrom(AssemblyPath);
+                var type = assembly.GetType(TypeName, throwOnError: true)!;
+                return Activator.CreateInstance(type, args)!;
 #endif
+            }
+            catch (Exception ex)
+            {
+                if (ex is TargetInvocationException)
+                    ex = ex.InnerException;
+                throw new ExtensibilityException("Error in constructing extension object", ex);
+            }
         }
 
 #endregion