XCTAssertEqual with Optional (not Equatable)

I would like to make the following in assertion:

XCTAssertEqual(sut.dataSource?.delegate, userInterface, "Data source's delegate should be the user interface")

The properties dataSource and delegate are Optionals. I tried unwrapping them with let assignments, but it essentially boils down to either

Generic parameter 'T' cannot be bound to non-@objc protocol type 'FetchedResultsControllerDataSourceDelegate'

or

Type 'FetchedResultsControllerDataSourceDelegate?' does not conform to protocol 'Equatable'

What can I do to assert that the optional relationships are properly set up?