public void GetDieAverage_shouldWork() { var diceService = new DiceService(); diceService.GetDieAverage(6).Should().Be(4); diceService.GetDieAverage(8).Should().Be(5); diceService.GetDieAverage(10).Should().Be(6); diceService.GetDieAverage(12).Should().Be(7); // maybe you're playing with some bizarre house rules diceService.GetDieAverage(7).Should().Be(4); }