BAEL-7238 Inject mock into Spy object in Mockito

- added "library" service to demonstrate mockito injection features
- updated mockito version to 5.10

testing-modules/mockito-2/pom.xml

@@ -24,11 +24,18 @@
             <version>${mockito.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>compile</scope>
+        </dependency>
     </dependencies>
 
     <properties>
         <mockito-inline.version>4.8.1</mockito-inline.version>
-        <mockito.version>5.9.0</mockito.version>
+        <mockito.version>5.10.0</mockito.version>
+        <lombok.version>1.18.30</lombok.version>
     </properties>
 
 </project>

testing-modules/mockito-2/src/main/java/com/baeldung/injectmockintospy/Book.java

@@ -0,0 +1,21 @@
+package com.baeldung.injectmockintospy;
+
+import java.time.ZonedDateTime;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+@Data
+@AllArgsConstructor
+public class Book {
+    private String name;
+    private String author;
+    private long timesTaken;
+    private ZonedDateTime returnDate;
+
+    public Book(String name, String author, long timesTaken) {
+        this.name = name;
+        this.author = author;
+        this.timesTaken = timesTaken;
+    }
+}

testing-modules/mockito-2/src/main/java/com/baeldung/injectmockintospy/BookControlService.java

@@ -0,0 +1,33 @@
+package com.baeldung.injectmockintospy;
+
+import java.time.ZonedDateTime;
+
+import lombok.NoArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+
+@Slf4j
+@NoArgsConstructor
+public class BookControlService {
+
+    private StatisticService statisticService;
+    private RepairService repairService;
+
+    public void returnBook(Book book) {
+        book.setReturnDate(null);
+        statisticService.calculateAdded();
+        if(repairService.shouldRepair(book)){
+            log.info("Book should be repaired");
+        }
+    }
+
+    public void giveBook(Book book) {
+        book.setReturnDate(ZonedDateTime.now().plusDays(14L));
+        statisticService.calculateRemoved();
+    }
+
+    public BookControlService(StatisticService statisticService, RepairService repairService) {
+        this.statisticService = statisticService;
+        this.repairService = repairService;
+    }
+
+}

testing-modules/mockito-2/src/main/java/com/baeldung/injectmockintospy/BookStorageService.java

@@ -0,0 +1,28 @@
+package com.baeldung.injectmockintospy;
+
+import java.util.LinkedList;
+import java.util.List;
+
+import lombok.Getter;
+
+@Getter
+public class BookStorageService {
+
+    private BookControlService bookControlService;
+    private final List<Book> availableBooks = new LinkedList<>();
+
+    public BookStorageService(BookControlService bookControlService) {
+        this.bookControlService = bookControlService;
+    }
+
+    public void returnBook(Book book) {
+        availableBooks.add(book);
+        bookControlService.returnBook(book);
+    }
+
+    public void giveBook(Book book) {
+        availableBooks.remove(book);
+        bookControlService.giveBook(book);
+    }
+
+}

testing-modules/mockito-2/src/main/java/com/baeldung/injectmockintospy/RepairService.java

@@ -0,0 +1,12 @@
+package com.baeldung.injectmockintospy;
+
+import lombok.Getter;
+
+@Getter
+public class RepairService {
+
+    public boolean shouldRepair(Book book) {
+        return book.getTimesTaken() > 10;
+    }
+
+}

testing-modules/mockito-2/src/main/java/com/baeldung/injectmockintospy/StatisticService.java

@@ -0,0 +1,22 @@
+package com.baeldung.injectmockintospy;
+
+import lombok.Getter;
+
+@Getter
+public class StatisticService {
+
+    private long todaysActions;
+
+    public void calculateAdded() {
+        todaysActions++;
+    }
+
+    public void calculateRemoved() {
+        todaysActions--;
+    }
+
+    public void reset() {
+        todaysActions = 0L;
+    }
+
+}

testing-modules/mockito-2/src/test/java/com/baeldung/injectmockintospy/MultipleInjectMockAndManualSpyWithExtensionUnitTest.java

@@ -0,0 +1,32 @@
+package com.baeldung.injectmockintospy;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+public class MultipleInjectMockAndManualSpyWithExtensionUnitTest {
+    @InjectMocks
+    private BookStorageService bookStorageService;
+    @InjectMocks
+    private BookControlService bookControlService = Mockito.spy(BookControlService.class);
+    @Mock
+    private StatisticService statisticService;
+    @Mock
+    private RepairService repairService;
+
+    @Test
+    void whenInjectMockUsedWithManualSpy_thenMockitoCanInjectMocks() {
+        Book book = new Book("Some name", "Some author", 355);
+        bookStorageService.returnBook(book);
+
+        Assertions.assertEquals(1, bookStorageService.getAvailableBooks().size());
+        Mockito.verify(bookControlService).returnBook(book);
+        Mockito.verify(statisticService).calculateAdded();
+        Mockito.verify(repairService).shouldRepair(book);
+    }
+}

testing-modules/mockito-2/src/test/java/com/baeldung/injectmockintospy/MultipleInjectMockAndManualSpyWithOpenMocksUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.injectmockintospy;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+
+public class MultipleInjectMockAndManualSpyWithOpenMocksUnitTest {
+
+    @InjectMocks
+    private BookStorageService bookStorageService;
+    @InjectMocks
+    private BookControlService bookControlService;
+    @Mock
+    private StatisticService statisticService;
+    @Mock
+    private RepairService repairService;
+    private AutoCloseable closeable;
+
+    @BeforeEach
+    public void openMocks() {
+        bookControlService = Mockito.spy(BookControlService.class);
+        closeable = MockitoAnnotations.openMocks(this);
+    }
+
+    @AfterEach
+    public void releaseMocks() throws Exception {
+        closeable.close();
+    }
+
+    @Test
+    void whenInjectMockUsedWithManualSpy_thenMockitoCanInjectMocks() {
+        Book book = new Book("Some name", "Some author", 355);
+        bookStorageService.returnBook(book);
+
+        Assertions.assertEquals(1, bookStorageService.getAvailableBooks().size());
+
+        Mockito.verify(bookControlService).returnBook(book);
+        Mockito.verify(statisticService).calculateAdded();
+        Mockito.verify(repairService).shouldRepair(book);
+    }
+}

testing-modules/mockito-2/src/test/java/com/baeldung/injectmockintospy/MultipleInjectMockAndMockitoSpyDoesnotWorkUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.injectmockintospy;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.Spy;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+public class MultipleInjectMockAndMockitoSpyDoesnotWorkUnitTest {
+    @InjectMocks
+    private BookStorageService bookStorageService;
+    @InjectMocks
+    @Spy
+    private BookControlService bookControlService;
+    @Mock
+    private StatisticService statisticService;
+    @Mock
+    private RepairService repairService;
+
+    @Test
+    @Disabled("test is not intended to work, it is here to show that such mock setup doesn't work")
+    void whenInjectMockUsedWithMockitoSpy_thenMockitoCannotInjectObjectProperly() {
+        Book book = new Book("Some name", "Some author", 355);
+        bookStorageService.returnBook(book);
+
+        Assertions.assertEquals(1, bookStorageService.getAvailableBooks().size());
+        Mockito.verify(bookControlService).returnBook(book);
+        Mockito.verify(statisticService).calculateAdded();
+        Mockito.verify(repairService).shouldRepair(book);
+    }
+}

testing-modules/mockito-2/src/test/java/com/baeldung/injectmockintospy/SingleInjectMockAndAnnotatedSpyUnitTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.injectmockintospy;
+
+import java.time.ZonedDateTime;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.Spy;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+public class SingleInjectMockAndAnnotatedSpyUnitTest {
+    @Spy
+    @InjectMocks
+    private BookControlService bookControlService;
+    @Mock
+    private StatisticService statisticService;
+    @Spy
+    private RepairService repairService;
+
+    @Test
+    void whenOneInjectMockWithSpy_thenHierarchySuccessfullyInitialized() {
+        Book book = new Book("Some name", "Some author", 355, ZonedDateTime.now());
+        bookControlService.returnBook(book);
+
+        Assertions.assertNull(book.getReturnDate());
+        Mockito.verify(statisticService).calculateAdded();
+        Mockito.verify(repairService).shouldRepair(book);
+    }
+}

testing-modules/mockito-2/src/test/java/com/baeldung/injectmockintospy/SingleInjectMockAndManualSpyWithReflectionUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.injectmockintospy;
+
+import java.lang.reflect.Field;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+public class SingleInjectMockAndManualSpyWithReflectionUnitTest {
+    @InjectMocks
+    private BookStorageService bookStorageService;
+    @Mock
+    private StatisticService statisticService;
+    @Mock
+    private RepairService repairService;
+    private BookControlService bookControlService;
+
+    @BeforeEach
+    public void openMocks() throws Exception {
+        bookControlService = Mockito.spy(new BookControlService(statisticService, repairService));
+        injectSpyToTestedMock(bookStorageService, bookControlService);
+    }
+
+    private void injectSpyToTestedMock(BookStorageService bookStorageService, BookControlService bookControlService) throws NoSuchFieldException, IllegalAccessException {
+        Field bookControlServiceField = BookStorageService.class.getDeclaredField("bookControlService");
+        bookControlServiceField.setAccessible(true);
+        bookControlServiceField.set(bookStorageService, bookControlService);
+    }
+
+    @Test
+    void whenManualSpyInjectedToTestesClass_thenHierarchySuccessfullyInitialized() {
+        Book book = new Book("Some name", "Some author", 355);
+        bookStorageService.returnBook(book);
+
+        Assertions.assertEquals(1, bookStorageService.getAvailableBooks().size());
+        Mockito.verify(bookControlService).returnBook(book);
+        Mockito.verify(statisticService).calculateAdded();
+        Mockito.verify(repairService).shouldRepair(book);
+    }
+}