Belma Jakupovic - Mockito additional answers (#9041)

testing-modules/mockito-2/src/test/java/com/baeldung/mockito/additionalanswers/BookServiceUnitTest.java

@@ -0,0 +1,68 @@
+package com.baeldung.mockito.additionalanswers;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.AdditionalAnswers;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.MockitoJUnitRunner;
+import static org.junit.Assert.assertEquals;
+import static org.mockito.ArgumentMatchers.any;
+
+@RunWith(MockitoJUnitRunner.class)
+public class BookServiceUnitTest {
+    @InjectMocks
+    private BookService bookService;
+
+    @Mock
+    private BookRepository bookRepository;
+
+    @Test
+    public void givenSaveMethodMocked_whenSaveInvoked_ThenReturnFirstArgument_UnitTest() {
+        Book book = new Book("To Kill a Mocking Bird", "Harper Lee", 256);
+        Mockito.when(bookRepository.save(any(Book.class))).then(AdditionalAnswers.returnsFirstArg());
+
+        Book savedBook = bookService.save(book);
+
+        assertEquals(savedBook, book);
+    }
+
+    @Test
+    public void givenCheckifEqualsMethodMocked_whenCheckifEqualsInvoked_ThenReturnSecondArgument_UnitTest() {
+        Book book1 = new Book(1L, "The Stranger", "Albert Camus", 456);
+        Book book2 = new Book(2L, "Animal Farm", "George Orwell", 300);
+        Book book3 = new Book(3L, "Romeo and Juliet", "William Shakespeare", 200);
+
+        Mockito.when(bookRepository.checkIfEquals(any(Book.class), any(Book.class), any(Book.class))).then(AdditionalAnswers.returnsSecondArg());
+
+        Book secondBook = bookService.checkifEquals(book1, book2, book3);
+
+        assertEquals(secondBook, book2);
+    }
+
+    @Test
+    public void givenCheckifEqualsMethodMocked_whenCheckifEqualsInvoked_ThenReturnLastArgument_UnitTest() {
+        Book book1 = new Book(1L, "The Stranger", "Albert Camus", 456);
+        Book book2 = new Book(2L, "Animal Farm", "George Orwell", 300);
+        Book book3 = new Book(3L, "Romeo and Juliet", "William Shakespeare", 200);
+
+        Mockito.when(bookRepository.checkIfEquals(any(Book.class), any(Book.class), any(Book.class))).then(AdditionalAnswers.returnsLastArg());
+
+        Book lastBook = bookService.checkifEquals(book1, book2, book3);
+        assertEquals(lastBook, book3);
+    }
+
+    @Test
+    public void givenCheckifEqualsMethodMocked_whenCheckifEqualsInvoked_ThenReturnArgumentAtIndex_UnitTest() {
+        Book book1 = new Book(1L, "The Stranger", "Albert Camus", 456);
+        Book book2 = new Book(2L, "Animal Farm", "George Orwell", 300);
+        Book book3 = new Book(3L, "Romeo and Juliet", "William Shakespeare", 200);
+
+        Mockito.when(bookRepository.checkIfEquals(any(Book.class), any(Book.class), any(Book.class))).then(AdditionalAnswers.returnsArgAt(1));
+
+        Book bookOnIndex = bookService.checkifEquals(book1, book2, book3);
+
+        assertEquals(bookOnIndex, book2);
+    }
+}