Add back test class I accidentally deleted (dotnet#48)

server/Microsoft.CodeAnalysis.LanguageServer.UnitTests/ServerInitializationTests.cs

@@ -0,0 +1,57 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.VisualStudio.LanguageServer.Protocol;
+using Xunit.Abstractions;
+
+namespace Microsoft.CodeAnalysis.LanguageServer.UnitTests;
+
+public class ServerInitializationTests : AbstractLanguageServerHostTests
+{
+    public ServerInitializationTests(ITestOutputHelper testOutputHelper) : base(testOutputHelper)
+    {
+    }
+
+    [Fact]
+    public async Task TestServerHandlesTextSyncRequestsAsync()
+    {
+        await using var server = await CreateLanguageServerAsync();
+        var document = new VersionedTextDocumentIdentifier { Uri = new Uri(@"C:\file.cs") };
+        var response = await server.ExecuteRequestAsync<DidOpenTextDocumentParams, object>(Methods.TextDocumentDidOpenName, new DidOpenTextDocumentParams
+        {
+            TextDocument = new TextDocumentItem
+            {
+                Uri = document.Uri,
+                Text = "Write"
+            }
+        }, CancellationToken.None);
+
+        // These are notifications so we should get a null response (but no exceptions).
+        Assert.Null(response);
+
+        response = await server.ExecuteRequestAsync<DidChangeTextDocumentParams, object>(Methods.TextDocumentDidChangeName, new DidChangeTextDocumentParams
+        {
+            TextDocument = document,
+            ContentChanges = new[]
+            {
+               new TextDocumentContentChangeEvent
+               {
+                   Range = new VisualStudio.LanguageServer.Protocol.Range { Start = new Position(0, 0), End = new Position(0, 0) },
+                   Text = "Console."
+               }
+            }
+        }, CancellationToken.None);
+
+        // These are notifications so we should get a null response (but no exceptions).
+        Assert.Null(response);
+
+        response = await server.ExecuteRequestAsync<DidCloseTextDocumentParams, object>(Methods.TextDocumentDidCloseName, new DidCloseTextDocumentParams
+        {
+            TextDocument = document
+        }, CancellationToken.None);
+
+        // These are notifications so we should get a null response (but no exceptions).
+        Assert.Null(response);
+    }
+}