public void ReturnNull_WhenTryingToAcceptOwnChallenge()
        {
            var initialChallenger = "Crimson";
            var acceptingOpponent = "Brendan";

            var duelingSystem = new DuelingSystem(new Mock <IChatClient>().Object, new FakeActionSystem());

            duelingSystem.RequestDuel(initialChallenger, acceptingOpponent);

            Duel challenges = duelingSystem.GetChallenges(initialChallenger, acceptingOpponent);

            challenges.Should().BeNull();
        }
        public void ReturnDuel_WhenAlreadyAnOpponent()
        {
            var initialChallenger = "Crimson";
            var acceptingOpponent = "Brendan";

            var duelingSystem = new DuelingSystem(new Mock <IChatClient>().Object, new FakeActionSystem());

            duelingSystem.RequestDuel(initialChallenger, acceptingOpponent);

            Duel challenges = duelingSystem.GetChallenges(acceptingOpponent, initialChallenger);

            challenges.Should().NotBeNull();
        }