From 463518332ed124746b5df8b34cfc7f3e0fbf475f Mon Sep 17 00:00:00 2001
From: khalidabuhakmeh <khalidabuhakmeh@gmail.com>
Date: Wed, 4 Jun 2025 11:41:01 -0400
Subject: [PATCH] Add unit test to verify handling of missing client in session
 coordination

Ensure `DefaultSessionCoordinationService` does not attempt logout for missing or null clients by introducing a dedicated test.
---
 .../DefaultSessionCoordinationServiceTests.cs | 39 +++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 identity-server/test/IdentityServer.UnitTests/Services/Default/DefaultSessionCoordinationServiceTests.cs

diff --git a/identity-server/test/IdentityServer.UnitTests/Services/Default/DefaultSessionCoordinationServiceTests.cs b/identity-server/test/IdentityServer.UnitTests/Services/Default/DefaultSessionCoordinationServiceTests.cs
new file mode 100644
index 000000000..1873345fd
--- /dev/null
+++ b/identity-server/test/IdentityServer.UnitTests/Services/Default/DefaultSessionCoordinationServiceTests.cs
@@ -0,0 +1,39 @@
+using System.Threading.Tasks;
+using Duende.IdentityServer.Configuration;
+using Duende.IdentityServer.Models;
+using Duende.IdentityServer.Services;
+using Duende.IdentityServer.Stores;
+using Microsoft.Extensions.Logging.Abstractions;
+using Shouldly;
+using UnitTests.Endpoints.EndSession;
+using Xunit;
+
+namespace UnitTests.Services.Default;
+
+public class DefaultSessionCoordinationServiceTests
+{
+    public DefaultSessionCoordinationService Service;
+
+    [Fact]
+    public async Task Handles_missing_client_null_reference()
+    {
+        var stubBackChannelLogoutClient = new StubBackChannelLogoutClient();
+        Service = new DefaultSessionCoordinationService(
+            new IdentityServerOptions(),
+            new InMemoryPersistedGrantStore(),
+            new InMemoryClientStore([]),
+            stubBackChannelLogoutClient,
+            new NullLogger<DefaultSessionCoordinationService>());
+        
+        await Service.ProcessExpirationAsync(new UserSession
+        {
+            ClientIds = ["not_found"],
+            SessionId = "1",
+            SubjectId = "1"
+        });
+        
+        stubBackChannelLogoutClient
+            .SendLogoutsWasCalled
+            .ShouldBeFalse();
+    }
+}
\ No newline at end of file