Spring boot field injection with autowire not working in JUnit test

Question

I want to inject DeMorgenArticleScraper in a test.

@RunWith(SpringJUnit4ClassRunner.class)
public class DeMorgenArticleScraperTest {

    @Autowired
    priv         


        

Answer 1

I replaced

@RunWith(SpringJUnit4ClassRunner.class)

with

@SpringBootTest
@RunWith(SpringRunner.class)

This appears to be working fine: I see Spring boot firing up and loading beans. I'll keep this question open for a short while for better suggestions.

Answer 2

I have the same problem.

1. There is service, which I want to inject for testing but I want to test only platformToSql(..) method without launching whole Spring Boot application.

   @Service
   public class ConverterToSqlImpl implements IConverterToSql {
   
       private final ISomeRepository someRepository;
       private final IUtilService utilService;
   
       public ConverterToSqlMainConstructorServiceImpl(
               IWorkerUtilService workerUtilService,
               ISomeRepository someRepository) {
           this.utilService = utilService;
           this.someRepository = someRepository;
       }
   
       @Override
       public String platformToSql(String platformName) {
           return "platform='" + platformName + "'";
       }
   
       @Override
       public String methodWhichUseRepositoryAndUtilBeans() {
           // some code which is not interested us
       }
   }
   

2. I create test class. It is necessary to mock beans because they are not need for test method.

   @RunWith(SpringRunner.class)
   @SpringBootTest(classes = {ConverterToSqlImpl.class})
   //@ContextConfiguration(classes = {ConverterToSqlImpl.class})
   @MockBeans({@MockBean(IUtilService.class), @MockBean(ISomeRepository.class)})
   public class SqlConverterConstructorTest {
   
       @Autowired
       private IConverterToSqlMainConstructorService convertToSql;
   
       @Test
       public void platformTest() {
           String platformSql = convertToSql.platformToSql("PLATFORM_1");
           String expectedSql = "platform='PLATFORM_1'";
           Assert.assertEquals(platformSql, expectedSql);
       }
   }
   

@SpringBootTest(classess = {}) load to ApplicationContext only classess which are pointed out in classess section, not whole application with all beans will be lauched.

Also, as alternative to @SpringBootTest with classes={..}, you can uncomment line with @ContextConfiguration. It is plain old style.

Answer 3

@SpringBootTest is fairly heavyweight, and for all intents and purpose will load your entire application, https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-testing.html#boot-features-testing-spring-boot-applications, it's fairly heavyweight and dramatically affects test time. Depending on what you are trying to test you may want to look into

• Slice tests e.g. @JsonTest, @DataJpaTest, @WebMvcTest etc. , https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-testing.html#boot-features-testing-spring-boot-applications-testing-autoconfigured-tests. Benefit of these tests are not only will they not load everything, thus faster, but will try to hunt out the relevant configurations.
• Plain old @ContextConfigurationand point to the relevant @Configuration's required to load beans needed for the test https://docs.spring.io/spring/docs/current/spring-framework-reference/testing.html#contextconfiguration