Add macOS CI job and regression test for Cleanup(block: false) bounded time

Agent-Logs-Url: https://github.com/zeromq/netmq/sessions/18a93bf8-a14c-4c0d-9f27-b797b58f300f

Co-authored-by: drewnoakes <[email protected]>

Author: Copilot

.github/workflows/CI.yml

@@ -15,6 +15,22 @@ jobs:
       run: dotnet build src/NetMQ.sln /p:Configuration=Release /verbosity:minimal
     - name: test net10.0
       run: dotnet test -v n -p:ParallelizeTestCollections=false --configuration Release --no-build -f net10.0 src/NetMQ.Tests/NetMQ.Tests.csproj
+  macos:
+    runs-on: macos-latest
+    permissions:
+      contents: read
+    env:
+      DOTNET_NOLOGO: true
+    steps:
+    - uses: actions/checkout@v6
+    - uses: actions/setup-dotnet@v5
+      with:
+        dotnet-version: 10.0.x
+    - run: dotnet restore src/NetMQ.sln
+    - name: build
+      run: dotnet build src/NetMQ.sln /p:Configuration=Release /verbosity:minimal
+    - name: test net10.0
+      run: dotnet test -v n -p:ParallelizeTestCollections=false --configuration Release --no-build -f net10.0 src/NetMQ.Tests/NetMQ.Tests.csproj
   windows:
     runs-on: windows-latest
     env:

src/NetMQ.Tests/CleanupTests.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Diagnostics;
+using System.Threading;
 using NetMQ.Sockets;
 using Xunit;
 
@@ -62,5 +63,21 @@ public void NoBlockNoDispose()
 
             NetMQConfig.Cleanup(block: false);
         }
+
+        [Fact]
+        public void NoBlockCompletesInBoundedTime()
+        {
+            // Regression test for https://github.com/zeromq/netmq/issues/1040
+            // Cleanup(block: false) must return quickly even when a socket has not been
+            // disposed and the internal poller is actively calling Socket.Select.
+            // On macOS, Socket.Select can block indefinitely when passed both a read list
+            // and an error list, causing Cleanup to hang forever without this guard.
+            _ = new DealerSocket(">tcp://localhost:5557"); // intentionally not disposed
+
+            var thread = new Thread(() => NetMQConfig.Cleanup(block: false));
+            thread.Start();
+            Assert.True(thread.Join(TimeSpan.FromSeconds(10)),
+                "Cleanup(block: false) did not complete within 10 seconds");
+        }
     }
 }