Mockito Object Injection

Inject Strings (or other objects) into your @InjectMocks targets [objects under test] without booting a Spring, Weld, CDI, Arquillian, EJB, or other container. Super lightweight and easy to use. Skip straight to Examples and Usage if you know what you're looking for.

Problem

Take this Spring Controller (or if you're using the far superior and modern CDI framework, imagine this is @AppplicationScoped)

@Controller
public class MyController {
 @Value("securityEnabled")
 private Boolean securityEnabled;
 @Autowired
 private Authenticator auther;
 @Autowired
 private Logger log;

 public void doSomething() {
  if (securityEnabled) {
    auther.something();
  } else {
    log.warn("sec disabled");
  }
 }
}

If you wanted to write a true unit test* with no external dependencies, you'd probably want to use Mockito mock your dependencies:

@ExtendWith({ MockitoExtension.class })
public class MyControllerTest {
 @InjectMocks
 private MyController myController;
 @Mock
 private Logger log;
 @Mock
 private Authenticator auther;
  
  public void testDoSomething() throws Exception {
   myController.doSomething();
   // results in NPE
  }
 }

Examples

This JUnit5 extension allows you to arbitrarily set any field on your @InjectMocks [class under test] target. The injections happen very late; they happen when you call any non-private method on the class under test.

import com.github.exabrial.junit5.injectmap.InjectMap;
import com.github.exabrial.junit5.injectmap.InjectMapExtension;

@ExtendWith({ MockitoExtension.class, InjectMapExtension.class })
public class MyControllerTest {
 @InjectMocks
 private MyController myController;
 @Mock
 private Logger log;
 @Mock
 private Authenticator auther;
 @InjectMap
 private Map<String, Object> injectMap = new HashMap<>();
 
 @BeforeEach
 public void beforeEach() throws Exception {
  injectMap.put("securityEnabled", Boolean.TRUE);
 }

 @AfterEach
 public void afterEach() throws Exception {
  injectMap.clear();
 }
  
 public void testDoSomething_secEnabled() throws Exception {
  myController.doSomething();
  // wahoo no NPE! Test the "if then" half of the branch
 }
  
 public void testDoSomething_secDisabled() throws Exception {
  injectMap.put("securityEnabled", Boolean.FALSE);
  myController.doSomething();
  // wahoo no NPE! Test the "if else" half of branch
 }
}

License

All files are licensed Apache Source License 2.0. Please consider contributing any improvements you make back to the project.

Usage

Maven Coordinates:

<dependency>
 <groupId>org.junit.jupiter</groupId>
 <artifactId>junit-jupiter-api</artifactId>
 <version>5.2.0</version>
 <scope>test</scope>
</dependency>
<dependency>
 <groupId>org.mockito</groupId>
 <artifactId>mockito-core</artifactId>
 <version>2.22.0</version>
 <scope>test</scope>
</dependency>
<dependency>
 <groupId>com.github.exabrial</groupId>
 <artifactId>mockito-object-injection</artifactId>
 <version>1.0.0</version>
 <scope>test</scope>
</dependency>

The final note is that it should extraordinarily obvious that per-test forking will produce undefined results when using @InjectMocks, and as such, per-test forking is not thread-safe for this test extension.

djr4488/mockito-object-injection

Mockito Object Injection

Problem

Examples

License

Usage