diff --git a/DigitalData.Auth.Tests/Client/AuthClientTests.cs b/DigitalData.Auth.Tests/Client/AuthClientTests.cs
index 22e88e2..ac35dbf 100644
--- a/DigitalData.Auth.Tests/Client/AuthClientTests.cs
+++ b/DigitalData.Auth.Tests/Client/AuthClientTests.cs
@@ -9,7 +9,7 @@ public class AuthClientTests
 {
     private IAuthClient _client;
 
-    private static ServiceProvider Build(Action<ClientParams> options) => new ServiceCollection()
+    private readonly static Func<Action<ClientParams>, ServiceProvider> Build = options => new ServiceCollection()
         .AddAuthHubClient(options)
         .BuildServiceProvider();