public void bookCalculatesAnAverageGrade() { //arrange var book = new InMemoryBook(""); book.AddGrade(89.1); book.AddGrade(90.5); book.AddGrade(77.3); //act var result = book.Getstat(); //assert Assert.Equal(85.6, result.average, 1); Assert.Equal(90.5, result.high, 1); Assert.Equal(77.3, result.low, 1); Assert.Equal('B', result.letter); }