public void ShouldApplyPercentageMana()
 {
     var p = new Player();
     p.LevelUp();
     p.ChooseSkill(new PathOfTheWizard());
     p.GainMana(50);
     p.AddModifier(new ManaBonusPercentage(50));
     Assert.IsTrue(p.BonusMana == 100);
 }