Can't mock method that takes Func<Dictionary<string,string>>

[Uriah]

Here is my attempt to mock the interface (I actually want to return a value, but throw just to make it easier to identify):

var cache = Mock.Create<ICache>();
_cacheFactoryMock.Arrange(m => m.Application).Returns(cache);
cache.Arrange(m => m.GetOrAdd(Arg.AnyString, Arg.IsAny<Func<Dictionary<string, string>>>, Arg.IsAny<DateTime>(), Arg.IsAny<TimeSpan>(), null)).Throws(new DivideByZeroException());

Here is the invocation:

return _caches.Application.GetOrAdd(
    string.Format(CacheKeyFormat, groupName),
    () => _ldapService.FindLdapUserEmailsInGroup(groupName),
    DateTime.Now.AddDays(1),
    Cache.NoSlidingExpiration
    );

 
Here is the method signature of FindLdapUserEmailsInGroup:

Dictionary<string, string> FindLdapUserEmailsInGroup(string groupName);

The pertinent part of the cachefactory interface:

public interface ICacheFactory
{
        ICache Application { get; }
}

The pertinent part of ICache:

public interface ICache
{
         TItem GetOrAdd<TItem, TState>(string key, Func<TState, TItem> getValue, TState state, DateTime absoluteExpiration, TimeSpan slidingExpiration, object dependencies = default(object));

        TItem GetOrAdd<TItem>(string key, Func<TItem> getValue, DateTime absoluteExpiration, TimeSpan slidingExpiration, object dependencies = default(object));
}

I'm not sure where I am going wrong.  I have tried several permutations of the dependencies object (using null, default etc), and I'm not sure what could be wrong with the Func<Dictionary<string,string>> arg but nothing I have done so far is getting the arrange to take effect.  Any guidance is appreciated.

[Stefan]

Hello Uriah,

It's hard to tell what might be wrong. I see you arrange _cacheFactoryMock.Arrange(m => m.Application)but then use  _caches.Application - it's hard to tell if they're related. Could you wrap the all the bits into a small repro project and attach it to this ticket for investigation, please?

Regards,
Stefan
Telerik