Use Mockito in Junit

Mockito

package testMockito;

import java.util.List;

public class Book {

private String isbn;
private String title;
private List<String> authors;
private String publication;
private Integer yearOfPublication;
private Integer numberOfPages;
private String image;

public Book(String isbn, String title, List<String> authors,
String publication, Integer yearOfPublication,
Integer numberOfPages, String image) {

this.isbn = isbn;
this.title = title;
this.authors = authors;
this.publication = publication;
this.yearOfPublication = yearOfPublication;
this.numberOfPages = numberOfPages;
this.image = image;

}

public String getIsbn() {
return isbn;
}

public String getTitle() {
return title;
}

public List<String> getAuthors() {
return authors;
}

public String getPublication() {
return publication;
}

public Integer getYearOfPublication() {
return yearOfPublication;
}

public Integer getNumberOfPages() {
return numberOfPages;
}

public String getImage() {
return image;
}
}

package testMockito;

import java.util.Collections;
import java.util.List;

public class BookDAL {
private static BookDAL bookDAL = new BookDAL();

public List<Book> getAllBooks(){
return Collections.EMPTY_LIST;
}

public Book getBook(String isbn){
return null;
}

public String addBook(Book book){
return book.getIsbn();
}

public String updateBook(Book book){
return book.getIsbn();
}

public static BookDAL getInstance(){
return bookDAL;
}

}

package testMockito;

import static org.junit.Assert.*;

import java.util.Arrays;
import java.util.List;

import org.junit.BeforeClass;
import org.junit.Ignore;
import org.junit.Test;
import org.junit.runner.RunWith;

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

import org.mockito.runners.MockitoJUnitRunner;

@RunWith(MockitoJUnitRunner.class)
public class BookDALTest {

private static BookDAL mockedBookDAL;
private static Book book1;
private static Book book2;

@BeforeClass
public static void setUp() {
// create mock object of BookDAL
mockedBookDAL = mock(BookDAL.class);

// create some instances of Book class.
book1 = new Book("8131721019", "Compilers Principles", Arrays.asList(
"D. Jeffrey Ulman", "Ravi Sethi", "Alfred V. Aho",
"Monica S. Lam"), "Pearson Education Singapore Pte Ltd", 2008,
1009, "BOOK_IMAGE");

book2 = new Book("9788183331630", "Let Us C 13th Edition",
Arrays.asList("Yashavant Kanetkar"), "BPB PUBLICATIONS", 2012,
675, "BOOK_IMAGE");

// Stubbing the methods of mocked BookDAL with mocked data.
when(mockedBookDAL.getAllBooks()).thenReturn(
Arrays.asList(book1, book2));
when(mockedBookDAL.getBook("8131721019")).thenReturn(book1);
when(mockedBookDAL.addBook(book1)).thenReturn(book1.getIsbn());
when(mockedBookDAL.updateBook(book1)).thenReturn(book1.getIsbn());
when(mockedBookDAL.updateBook(book2)).thenReturn(book2.getIsbn());
}

@Test
public void testGetAllBooks() {
List<Book> allBooks = mockedBookDAL.getAllBooks();
assertEquals(2, allBooks.size());
Book myBook = allBooks.get(0); // book1
assertEquals("8131721019", myBook.getIsbn());
assertEquals("Compilers Principles", myBook.getTitle());
assertEquals(4, myBook.getAuthors().size());
assertEquals((Integer) 2008, myBook.getYearOfPublication());
assertEquals((Integer) 1009, myBook.getNumberOfPages());
assertEquals("Pearson Education Singapore Pte Ltd",
myBook.getPublication());
assertEquals("BOOK_IMAGE", myBook.getImage());
}

@Test
public void testGetBook() {
String isbn = "81317
ae74
21019";

Book myBook = mockedBookDAL.getBook(isbn);

assertNotNull(myBook);
assertEquals(isbn, myBook.getIsbn());
assertEquals("Compilers Principles", myBook.getTitle());
assertEquals(4, myBook.getAuthors().size());
assertEquals("Pearson Education Singapore Pte Ltd",
myBook.getPublication());
assertEquals((Integer) 2008, myBook.getYearOfPublication());
assertEquals((Integer) 1009, myBook.getNumberOfPages());
}

@Test
public void testAddBook() {
String isbn = mockedBookDAL.addBook(book1);
assertNotNull(isbn);
assertEquals(book1.getIsbn(), isbn);

}

@Test
public void testUpdateBook() {
String isbn = mockedBookDAL.updateBook(book1);
assertNotNull(isbn);
assertEquals(book1.getIsbn(), isbn);
isbn = mockedBookDAL.updateBook(book2);
assertNotNull(isbn);
assertEquals(book2.getIsbn(), isbn);

}

@Ignore@Test
public void testGetInstance() {
fail("Not yet implemented");
}

}