public void BookReturnsLowestGrade() { // arrange var book = new InMemoryBook("Test Book"); book.AddGrade(99.9); book.AddGrade(49.3); book.AddGrade(39.3); book.AddGrade(29.3); book.AddGrade(19.3); var expected = 19.3; // act var actual = book.GetLowestGrade(); // assert Assert.Equal(actual, expected); }