Problems mocking SPList

Hi
I've looked through some posts here regarding mocking SPLists, but I couldn't find quite what I was looking for.

I have this simple method I want to test with Typemock:

public SPList GetListByListname(SPWeb web, string listName)
        {
            foreach (SPList list in web.Lists)
                if (list.Title == listName)
                    return list;
            return null;
        }

I've tried a lot of different things to be able to write a simple unit test to this method, but my test always returns null.
Probably because I have not figured out how to mock the list properly.

 [TestMethod]
        public void GetListByListname_ListExist_ReturnTrue()
        {
            // Arrange
            var fakeWeb = Isolate.Fake.Instance<SPWeb>();
            fakeWeb.Lists.Add("testList", "", SPListTemplateType.GenericList);
            fakeWeb.Lists.Add("testList2", "", SPListTemplateType.GenericList);
            Isolate.Swap.NextInstance<SPWeb>().With(fakeWeb);
           

            // Act
            ProductOfferProvider provider = new ProductOfferProvider();
            var newSPList = provider.GetListByListname(fakeWeb, "testList");
 
            // Assert
            Assert.IsNotNull(newSPList);
        }

I've also tried to fake the list (e.g. fakeList = Isolate.Fake.Instance<SPList>(); ), but I cannot figure out how to connect this object to my fakeWeb.

Any help is appreciated

Thanks