public async Task IgnoresNullValueReturnedFromTheServer()
        {
            var observables = createObservables(null);

            var transition = (Transition <IFetchObservables>)(await state.Start(observables).SingleAsync());

            transition.Result.Should().Be(state.Done);
            await dataSource.DidNotReceive().UpdateWithConflictResolution(Arg.Any <IThreadSafeTestModel>());
        }