在以下情况下，我应该如何编写JUnit测试？

Question

I am new in the Unit Testing. I have a class Ckeckout which main function is to print the amount to be paid for books. The user types the titles of the books in the command line, and based on some calculations I have to output the final price. Here is the Book class:

public class Book {
    private String title;
    private double price;
    private int year;

    public Book(String title, double price, int year) {
        super();
        this.title = title;
        this.price = price;
        this.year = year;
    }
}

And here is the Checkout class:

public class Checkout {

    private List<Book> books;

    public Checkout(List<Book> books) {
        super();
        this.books = books;
    }

    //calculate the final price
    private double getPrice(){
        //return some double
    }


}

What I want to test is just getPrice method. However, to do so, do I have to create list of Book objects in my CheckoutTest ? Also, I will have to verify the final result with some very long number (like 62.01997301). Isn't it easier, to test the main() method, since in my Unit test, there won't be any need to create the Book objects (I will work only with Strings ) and I can verify the output with shorter number (like 62.01)?

Answer 1

1. However, to do so, do I have to create list of Book objects in my CheckoutTest?:Generally and in any kind - yeah !

2. Also, I will have to verify the final result with some very long number (like 62.01997301): Naah , this depends on your targeting test/code quality! (for a "price" 2 digits should be sufficient (in any country!?))

3. Isn't it easier, to test the main() method, since in my Unit test, there won't be any need to create the Book objects (I will work only with Strings) and I can verify the output with shorter number (like 62.01)? Definitely! But with the current setup some (human) would have to check the console for "passing that test", for JUnit(and programmatically testing the value), you should/will need to make "getPrice() more visible" ... or in some way access its value.