public void ReturnBookReadable()
{
var author = "Author";
var title = "Title";
var callNumber = "Call Number";
var id = 1;
var book = new Book(author, title, callNumber, id);
var readable = $"ID:\t\t{book.ID}\nCall Number:\t{book.CallNumber}\nAuthor:\t\t{book.Author}\nTitle:\t\t{book.Title}";
Assert.Equal(readable, book.ToString());
}