public async Task When_creating_a_new_game_with_a_name_valid_then_a_new_game_should_be_created()
        {
            var gamesRepository   = Substitute.For <IGamesRepository>();
            var createGameHandler = new CreateGameHandler(gamesRepository, Substitute.For <IUnitOfWork>());

            var result = await createGameHandler.Handle(new CreateGame("Name"), default);

            await gamesRepository.ReceivedWithAnyArgs(1).AnyAsync(default, default);
        public void When_creating_a_game_with_existing_name_then_an_application_exception_should_be_thrown()
        {
            var gamesRepository = Substitute.For <IGamesRepository>();

            gamesRepository.AnyAsync(Arg.Any <Expression <Func <Game, bool> > >(), default).Returns(Task.FromResult(true));

            var createGameHandler = new CreateGameHandler(gamesRepository, Substitute.For <IUnitOfWork>());

            Func <Task <Unit> > action = async() => await createGameHandler.Handle(new CreateGame("Name"), default);

            action.Should().Throw <ApplicationException>().WithMessage(Messages.NameMustUnique);
        }