public void BookCalculatesStats() { //arrange var book = new InMemoryBook(""); book.AddGrade(13.3); book.AddGrade(22.3); book.AddGrade(23.3); //act var result = book.GetStatistic(); //assert Assert.Equal(23.3, result.High, 1); Assert.Equal(13.3, result.Low, 1); Assert.Equal(19.6, result.Average, 1); Assert.Equal('C', result.Letter); }