arrange tests

DigitalData.Core.Infrastructure/DependencyInjection.cs

@@ -16,6 +16,9 @@ public static class DependencyInjection
         options.Invoke(cfg);
         cfg.RegisterAllServices(services);
 
+        // register db repository
+        services.AddSingleton<IRepository, DbRepository>();
+
         // register db repository factory
         services.AddSingleton<IRepositoryFactory, DbRepositoryFactory>();