Clean up AssemblyResolver code

Author: Paul van Brenk

Nodejs/Product/TestAdapter/AssemblyResolver.cs

@@ -7,9 +7,12 @@
 
 namespace Microsoft.NodejsTools.TestAdapter
 {
-    internal sealed class AssemblyResolver : IDisposable
+    internal sealed class AssemblyResolver
     {
-        public AssemblyResolver()
+        private const string ResolveHandlerKey = "JavaScriptUnitTest_ResolveHandler";
+        private static AssemblyResolver resolver;
+
+        private AssemblyResolver()
         {
             // Use the setup API to find the VS install Dir, then build paths to the Private and Public Assemblies folders
             var installPath = GetVSInstallDir();
@@ -24,9 +27,19 @@ public AssemblyResolver()
             AppDomain.CurrentDomain.AssemblyResolve += this.OnAssemblyResolve;
         }
 
+        public static void SetupHandler()
+        {
+            var handler = AppDomain.CurrentDomain.GetData(ResolveHandlerKey);
+            if(handler == null)
+            {
+                resolver = new AssemblyResolver();
+                AppDomain.CurrentDomain.SetData(ResolveHandlerKey, "set");
+            }
+        }
+
         private readonly string[] probePaths;
 
-        internal static string GetVSInstallDir()
+        private static string GetVSInstallDir()
         {
             var vsTestFrameworkAssembly = typeof(ITestExecutor).Assembly;
             var testAdapterPath = vsTestFrameworkAssembly.Location;
@@ -58,10 +71,5 @@ private Assembly OnAssemblyResolve(object sender, ResolveEventArgs args)
             }
             return null;
         }
-
-        public void Dispose()
-        {
-            AppDomain.CurrentDomain.AssemblyResolve -= this.OnAssemblyResolve;
-        }
     }
 }

Nodejs/Product/TestAdapter/JavaScriptTestDiscoverer.cs

@@ -19,14 +19,9 @@ namespace Microsoft.NodejsTools.TestAdapter
     [DefaultExecutorUri(NodejsConstants.ExecutorUriString)]
     public partial class JavaScriptTestDiscoverer : ITestDiscoverer
     {
-        internal static AssemblyResolver AssemblyResolver { get; set; }
-
         public void DiscoverTests(IEnumerable<string> sources, IDiscoveryContext discoveryContext, IMessageLogger logger, ITestCaseDiscoverySink discoverySink)
         {
-            if (JavaScriptTestDiscoverer.AssemblyResolver == null)
-            {
-                JavaScriptTestDiscoverer.AssemblyResolver = new AssemblyResolver();
-            }
+            AssemblyResolver.SetupHandler();
             this.DiscoverTestsCore(sources, discoveryContext, logger, discoverySink);
         }
 

Nodejs/Product/TestAdapter/JavaScriptTestExecutor.cs

@@ -13,14 +13,14 @@ public class JavaScriptTestExecutor : ITestExecutor
 
         public void RunTests(IEnumerable<TestCase> tests, IRunContext runContext, IFrameworkHandle frameworkHandle)
         {
-            this.EnsureInitialized();
+            AssemblyResolver.SetupHandler();
             this.worker = new TestExecutorWorker(runContext, frameworkHandle);
             this.worker.RunTests(tests);
         }
 
         public void RunTests(IEnumerable<string> sources, IRunContext runContext, IFrameworkHandle frameworkHandle)
         {
-            this.EnsureInitialized();
+            AssemblyResolver.SetupHandler();
             this.worker = new TestExecutorWorker(runContext, frameworkHandle);
             this.worker.RunTests(sources, new JavaScriptTestDiscoverer());
         }
@@ -29,13 +29,5 @@ public void Cancel()
         {
             this.worker?.Cancel();
         }
-
-        private void EnsureInitialized()
-        {
-            if (JavaScriptTestDiscoverer.AssemblyResolver == null)
-            {
-                JavaScriptTestDiscoverer.AssemblyResolver = new AssemblyResolver();
-            }
-        }
     }
 }

Nodejs/Product/TestAdapter/PackageJsonTestDiscoverer.cs

@@ -18,6 +18,7 @@ public sealed class PackageJsonTestDiscoverer : ITestDiscoverer
     {
         public void DiscoverTests(IEnumerable<string> sources, IDiscoveryContext discoveryContext, IMessageLogger logger, ITestCaseDiscoverySink discoverySink)
         {
+            AssemblyResolver.SetupHandler();
             foreach (var source in sources)
             {
                 // we're only interested in package.json files here.

Nodejs/Product/TestAdapter/PackageJsonTestExecutor.cs

@@ -18,12 +18,14 @@ public void Cancel()
 
         public void RunTests(IEnumerable<string> sources, IRunContext runContext, IFrameworkHandle frameworkHandle)
         {
+            AssemblyResolver.SetupHandler();
             this.worker = new TestExecutorWorker(runContext, frameworkHandle);
             this.worker.RunTests(sources, new PackageJsonTestDiscoverer());
         }
 
         public void RunTests(IEnumerable<TestCase> tests, IRunContext runContext, IFrameworkHandle frameworkHandle)
         {
+            AssemblyResolver.SetupHandler();
             this.worker = new TestExecutorWorker(runContext, frameworkHandle);
             this.worker.RunTests(tests);
         }