Synchronize tests using stdio access.

Author: eiriktsarpalis

tests/ModelContextProtocol.Tests/Transport/StdioServerTransportTests.cs

@@ -10,6 +10,7 @@ namespace ModelContextProtocol.Tests.Transport;
 
 public class StdioServerTransportTests
 {
+    private static readonly SemaphoreSlim s_consoleSemaphore = new(initialCount: 1);
     private readonly McpServerOptions _serverOptions;
 
     public StdioServerTransportTests()
@@ -60,6 +61,8 @@ public async Task StartListeningAsync_Should_Set_Connected_State()
     [Fact]
     public async Task SendMessageAsync_Should_Send_Message()
     {
+        await s_consoleSemaphore.WaitAsync();
+
         TextReader oldIn = Console.In;
         TextWriter oldOut = Console.Out;
         try
@@ -86,6 +89,7 @@ public async Task SendMessageAsync_Should_Send_Message()
         {
             Console.SetOut(oldOut);
             Console.SetIn(oldIn);
+            s_consoleSemaphore.Release();
         }
     }
 
@@ -112,6 +116,8 @@ public async Task DisposeAsync_Should_Dispose_Resources()
     [Fact]
     public async Task ReadMessagesAsync_Should_Read_Messages()
     {
+        await s_consoleSemaphore.WaitAsync();
+
         var message = new JsonRpcRequest { Method = "test", Id = RequestId.FromNumber(44) };
         var json = JsonSerializer.Serialize(message, JsonSerializerOptionsExtensions.DefaultOptions);
 
@@ -137,6 +143,7 @@ public async Task ReadMessagesAsync_Should_Read_Messages()
         {
             Console.SetOut(oldOut);
             Console.SetIn(oldIn);
+            s_consoleSemaphore.Release();
         }
     }