diff --git a/Lombiq.Tests.UI/Services/OrchardCoreSetupConfiguration.cs b/Lombiq.Tests.UI/Services/OrchardCoreSetupConfiguration.cs
index 48948c476..56aa6969e 100644
--- a/Lombiq.Tests.UI/Services/OrchardCoreSetupConfiguration.cs
+++ b/Lombiq.Tests.UI/Services/OrchardCoreSetupConfiguration.cs
@@ -13,7 +13,7 @@ namespace Lombiq.Tests.UI.Services;
 /// </summary>
 public class OrchardCoreSetupConfiguration
 {
-    public static Func<Func<UITestContext, Task<Uri>>, string> DefaultSetupOperationIdentifierCalculator =
+    public static readonly Func<Func<UITestContext, Task<Uri>>, string> DefaultSetupOperationIdentifierCalculator =
         setupOperation => setupOperation.GetHashCode().ToTechnicalString();
 
     /// <summary>