Improve resource management in TestWorkspaceFixture

src/EditorFeatures/TestUtilities/Workspaces/TestWorkspaceFixture.cs

@@ -31,6 +31,9 @@ public TestWorkspace GetWorkspace(string markup, ExportProvider exportProvider =
         {
             if (TryParseXElement(markup, out var workspaceElement) && workspaceElement.Name == "Workspace")
             {
+                CloseTextView();
+                _workspace?.Dispose();
+
                 _workspace = TestWorkspace.CreateWorkspace(workspaceElement, exportProvider: exportProvider, workspaceKind: workspaceKind);
                 _currentDocument = _workspace.Documents.First(d => d.CursorPosition.HasValue);
                 Position = _currentDocument.CursorPosition.Value;

src/EditorFeatures/TestUtilities/Workspaces/TestWorkspace_XmlConsumption.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
 extern alias WORKSPACES;
 
 using System;
@@ -6,6 +7,7 @@
 using System.Collections.Immutable;
 using System.Collections.ObjectModel;
 using System.Globalization;
+using System.IO;
 using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Threading;
@@ -20,8 +22,6 @@
 using Microsoft.CodeAnalysis.VisualBasic;
 using Microsoft.VisualStudio.Composition;
 using Microsoft.VisualStudio.Text;
-using Microsoft.VisualStudio.Utilities;
-using Roslyn.Test.EditorUtilities;
 using Roslyn.Test.Utilities;
 using Roslyn.Utilities;
 using Xunit;
@@ -910,7 +910,13 @@ private static IList<MetadataReference> CreateReferenceList(TestWorkspace worksp
             var references = CreateCommonReferences(workspace, element);
             foreach (var reference in element.Elements(MetadataReferenceElementName))
             {
-                references.Add(MetadataReference.CreateFromFile(reference.Value));
+                // Read the image to an ImmutableArray<byte>, since the GC does a better job of tracking these than
+                // Marshal.AllocHGlobal and thus knowing when it's necessary to run finalizers to clean up old Metadata
+                // objects that are no longer in use. There are no public APIs available to directly dispose of these
+                // images, so we are relying on GC running finalizers to avoid OutOfMemoryException during tests.
+                var content = File.ReadAllBytes(reference.Value);
+                var peImage = ImmutableArrayExtensions.DangerousCreateFromUnderlyingArray(ref content);
+                references.Add(MetadataReference.CreateFromImage(peImage, filePath: reference.Value));
             }
 
             foreach (var metadataReferenceFromSource in element.Elements(MetadataReferenceFromSourceElementName))