bookTest.java prints out author arrayList, but not isbn

Question

Requirements: accommodate multiple authors using one of the components from the Java Collection Framework. Requires one book with an isbn and a Collection of authors. JUnit: Guidance for testValidate: Test for at least two cases (one case where the book properties hold the correct data types and are not empty nor hold a null value, one where they do not). Guidance for testEquals: Test for at least two cases (one case where authors and isbn match, one where they do not). Test for at least two authors. My teacher told me: testEquals you need to add isbn and two authors. Create an ArrayList. Add two authors to it. Create a Book object and add the ArrayList instance and the isbn. I think that's what I have done, the authors are printing, but the ISBNs are not. I am a total newbie and I am at a loss! Can anyone help?

EDIT/ADDITION I got the ISBN to print, but it is only printing the second isbn I have. What do I need to change to get both of them to print? Or does it matter?

Here is the output:

Testsuite: library.domain.BookTest
equals
Author List: [Bob Smith, Jane Doe]
ISBN: 67890
validate
Author List: [Bob Smith, Jane Doe]
ISBN: 67890
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.23 sec

------------- Standard Output ---------------
equals
Author List: [Bob Smith, Jane Doe]
ISBN: 67890
validate
Author List: [Bob Smith, Jane Doe]
ISBN: 67890
------------- ---------------- ---------------
test:
Deleting: /var/folders/k7/wpgy3lw91171qxlzt4pj0cfh0000gn/T/TEST-library.domain.BookTest.xml
BUILD SUCCESSFUL (total time: 1 second)

Here is my new page:

NEW BookTest.java

package library.domain;

import java.util.ArrayList;
import static org.junit.Assert.assertEquals;
import org.junit.Test;

public class BookTest {

    private ArrayList<String> authorList = new ArrayList<>();

    @Test
    public void testEquals()                //test Equals() for accuracy
    {
        System.out.println("equals");
        authorList.add("Bob Smith");
        Book book = new Book("12345", authorList);
        assertEquals("expected true", true, book.equals(book));
        authorList.add("Jane Doe");
        book = new Book("67890", authorList);
        assertEquals("expected true", true, book.equals(book));
        System.out.println("Author List: " + authorList);
        System.out.println("ISBN: " + book.getIsbn());
    }

    @Test
    public void testValidate()          //test Validate() for accuracy
    {
        System.out.println("validate");
        authorList.add("Bob Smith");
        Book book = new Book("12345", authorList);
        assertEquals("expected true", true, book.validate());
        authorList.add("Jane Doe");
        book = new Book("67890", authorList);
        assertEquals("expected true", true, book.validate());
        System.out.println("Author List: " + authorList);
        System.out.println("ISBN: " + book.getIsbn());
    }
}

Book.java

package library.domain;

import java.util.ArrayList;
import java.util.Objects;

public class Book {

    private String isbn;
    private ArrayList<String> authorList;

    public Book(String isbn, ArrayList<String> authorList)
    {
        this.isbn = isbn;
        this.authorList = authorList;
    }

    public String getIsbn()             //access to isbn and manages  next value
    {
        return isbn;
    }

    public void setIsbn(String isbn)            //assigns the input isbn to the data member isbn
    {
        this.isbn = isbn;
    }
//assigns the input author to the data member author

    public ArrayList<String> getAuthorList()
    {
        return authorList;
    }

    public void setAuthorList(ArrayList<String> authorList)
    {
        this.authorList = authorList;
    }

    @Override
    public boolean equals(Object obj)           //checks  equality of two objects - true if same, false if different
    {
        if (this == obj) {
            return true;
        }
        if (!(obj instanceof Book)) {
            return false;
        }

        Book book = (Book) obj;
        if (!this.isbn.equals(book.isbn)) {
            return false;
        }
        if (!this.authorList.equals(book.authorList)) {
            return false;
        }
        return true;
    }

    @Override
    public int hashCode()           //override hash
    {
        int hash = 7;
        hash = 97 * hash + Objects.hashCode(this.authorList);
        hash = 97 * hash + Objects.hashCode(this.isbn);
        return hash;
    }

    public boolean validate()           //validate isbn and author not null
    {
        if (isbn == null || isbn.equals("")) {
            return false;
        }
        if (authorList == null || authorList.equals("")) {
            return false;
        }
        {
            return true;
        }
    }
}

BookTest.java

package library.domain;

import java.util.ArrayList;
import static org.junit.Assert.assertEquals;
import org.junit.Test;

public class BookTest {

    private ArrayList<String> authorList = new ArrayList<>();
    private String isbn;

    @Test
    public void testEquals()                //test Equals() for accuracy
    {
        System.out.println("equals");
        authorList.add("Bob Smith");
        authorList.add("Jane Doe");
        Book book = new Book("12345", authorList);
        assertEquals("expected true", true, book.equals(book));
        System.out.println("Author List: " + authorList);
        System.out.println("ISBN: " + isbn);
    }

    @Test
    public void testValidate()          //test Validate() for accuracy
    {
        System.out.println("validate");
        authorList.add("Bob Smith");
        authorList.add("Jane Doe");
        Book book = new Book("12345", authorList);
        assertEquals("expected true", true, book.validate());
        System.out.println("Author List: " + authorList);
        System.out.println("ISBN: " + isbn);
    }
}

Answer 1

isbn in the test class is a local variable and you are not setting any values for the same. To check if object is being created correctly, try printing book.getAuthorList() and book.getIsbn()