Unity resolve exception

Question

I'm trying to execute the following in my Unit Test:

IUnityContainer container = new UnityContainer();
DependencyResolver.SetResolver(new UnityDependencyResolver(container));
var test = DependencyResolver.Current.GetService<IUnityContainer>();

I get the following error, not sure what's going on:

'System.NullReferenceException' occurred in Unity.Mvc5.dll but was not handled in user code