Fix test failures

Author: dibarbet

src/EditorFeatures/TestUtilities/LanguageServer/AbstractLanguageServerProtocolTests.cs

@@ -38,36 +38,9 @@ public abstract class AbstractLanguageServerProtocolTests
     {
         // TODO: remove WPF dependency (IEditorInlineRenameService)
         private static readonly TestComposition s_composition = EditorTestCompositions.LanguageServerProtocolWpf
-            .AddParts(typeof(TestLspWorkspaceRegistrationService))
             .AddParts(typeof(TestDocumentTrackingService))
             .RemoveParts(typeof(MockWorkspaceEventListenerProvider));
 
-        [Export(typeof(ILspWorkspaceRegistrationService)), PartNotDiscoverable]
-        internal class TestLspWorkspaceRegistrationService : ILspWorkspaceRegistrationService
-        {
-            private Workspace? _workspace;
-
-            [ImportingConstructor]
-            [Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
-            public TestLspWorkspaceRegistrationService()
-            {
-            }
-
-            public ImmutableArray<Workspace> GetAllRegistrations()
-            {
-                Contract.ThrowIfNull(_workspace, "No workspace has been registered");
-
-                return ImmutableArray.Create(_workspace);
-            }
-
-            public void Register(Workspace workspace)
-            {
-                Contract.ThrowIfTrue(_workspace != null);
-
-                _workspace = workspace;
-            }
-        }
-
         private class TestSpanMapperProvider : IDocumentServiceProvider
         {
             TService IDocumentServiceProvider.GetService<TService>()

src/VisualStudio/LiveShare/Test/AbstractLiveShareRequestHandlerTests.cs

@@ -21,8 +21,7 @@ namespace Microsoft.VisualStudio.LanguageServices.LiveShare.UnitTests
     public abstract class AbstractLiveShareRequestHandlerTests : AbstractLanguageServerProtocolTests
     {
         private static readonly TestComposition s_composition = LiveShareTestCompositions.Features.AddParts(
-            typeof(MockDocumentNavigationServiceFactory),
-            typeof(TestLspWorkspaceRegistrationService));
+            typeof(MockDocumentNavigationServiceFactory));
 
         private class MockHostProtocolConverter : IHostProtocolConverter
         {

src/Workspaces/CoreTestUtilities/TestExportJoinableTaskContext.cs

@@ -61,7 +61,9 @@ private static (JoinableTaskContext joinableTaskContext, SynchronizationContext
             return (new JoinableTaskContext(mainThread, synchronizationContext), synchronizationContext);
         }
 
+#pragma warning disable VSSDK005 // Use ThreadHelper.JoinableTaskContext singleton - N/A, used for test code
         [Export]
+#pragma warning restore VSSDK005 // Use ThreadHelper.JoinableTaskContext singleton - N/A, used for test code
         private JoinableTaskContext JoinableTaskContext
         {
             get;