Mocked bean in spring unit test not wired to AutoWired dependency - spring

Question

I am trying to write unit test for a class which has an Autowired dependency.
public class User {
#Autowired
private ServiceContext serviceContext;
User() {}
public String getToken() {
return serviceContext.getToken();
}
My Unit Test class to test getToken() method
#RunWith(SpringJUnit4ClassRunner.class)
public class UserTest() {
#MockBean
private ServiceContext serviceContext;
#BeforeTest
private void setup() {
when(serviceContext.getToken()).thenReturn("Token");
}
#Test
public void test() {
User user = new User();
assertEquals(user.getToken(), "Token");
}
}
When I run this test, there is a NullPointerException in getToken() of User . It says the serviceContext variable is null.
Why cant the mock bean which I created in the test be autowired to the dependency in User class ?
I also tried this test code -
#RunWith(SpringJUnit4ClassRunner.class)
public class UserTest() {
#MockBean
private ServiceContext serviceContext;
#InjectMocks
User useer = new User();
#BeforeTest
private void setup() {
when(serviceContext.getToken()).thenReturn("Token");
}
#Test
public void test() {
assertEquals(user.getToken(), "Token");
}
}
This also gives a NullPointerException saying that the serviceContext dependency in User class is null.
How do I unit test my User class methods using a mocked ServiceContext bean and wiring it to the User objects ?
I am using annotation based spring configuration and dont want to start the spring container to test this.
For running my application, I am using this-
#Configuration
#EnableConfigurationProperties(ApiProperties.class)
public class ServiceConfiguration {
#Bean
#Scope(value = ConfigurableBeanFactory.SCOPE_SINGLETON, proxyMode = ScopedProxyMode.TARGET_CLASS)
ServiceContext serviceContext(ApiProperties properties, Parameter param) {
final ServiceContext serviceContext = new ServiceContext(properties, param);
return serviceContext;
}
Do I need to add this class in my #SpringBootTest ?

Answer 1

How does spring know which context should be created?
You've only defined that the test should run with spring, but spring has no clue from where to load the configurations.
You should use #SpringBootTest annotation if you want to rely on spring boot configuration resolution rules or at some #ContextConfiguration to specify manually the configurations to load.