RhinoMocks Constraints with IsMatching() using Predicate

var mocks = new MockRepository();
var repository = mocks.StrictMock();
var controller = new AController(repository);
List items = new List {"foo"};
var modelObj = new ModelObj(items);

Predicate compareModelObjs =
delegate(ModelObj m) { return m.Items.AsEnumerable().SequenceEqual(items); }

repository.Expect(r => r.SaveModelObj(null)).Constraints(Is.Matching(compareModelObjs)).Return(true);
mocks.ReplayAll();
controller.Save(items);
mocks.VerifyAll();

Of course, you should probably write an Equals() method on the ModelObj.