public void ItRequiresPlayerRanks()
{
List<IPlayerRank> playerRanks = null;
var exception = Assert.Throws<ArgumentException>(() => PlayerRankValidator.ValidatePlayerRanks(playerRanks));
Assert.That(exception.Message, Is.EqualTo(PlayerRankValidator.EXCEPTION_MESSAGE_MUST_PASS_AT_LEAST_TWO_PLAYERS));
}