Spring Boot unit test constructor injection

Question

I'm using Spring Boot to create a REST API and write some unit tests on my controllers. I know that the recommended manner to inject beans in spring is the constructor injection. But when i add the @SpringBootTest annotation to my test class, I can not inject my controller class with constructor, I find myself obliged to use @Autowired.

Have some explanation and is there another way to use constructor injection with SpringBootTest.

@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT) class PersonControllerTest { @LocalServerPort private int port; @Autowired private PersonController controller; @Autowired private TestRestTemplate restTemplate; @Test public void greetingShouldReturnDefaultMessage() throws Exception { assertThat(this.restTemplate.getForObject("http://localhost:" + port + "/cvtech/Persons/", String.class)).contains("content"); } @Test public void contextLoads() throws Exception { assertThat(controller).isNotNull(); } @Test void findAllByJob() { } }

You don't want Spring and DI for Unit tests. Use it for Integration tests. If it's an integration test, I advice you look into MockMVC — Nico Van Belle
– Nico Van Belle, Commented Oct 30, 2020 at 9:16

dstibbe · Accepted Answer · 2022-06-27 09:21:20Z

For those using Kotlin, using field-injection means having to use lateinit var fields. Which is far from ideal.

It is possible to use constructor injection on SpringBoot tests however, using the @TestConstructor:

@ExtendWith(SpringExtension::class) @TestConstructor(autowireMode = ALL) @SpringBootTest( classes = [MyApplication::class], webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, ) internal class MyIntegrationTest( val beanA: BeanA, @Qualifier("some qualified") val beanB: BeanB, ) { ... // Tests can use the beans injected in the constructor without any problems ... }

Nico Van Belle · Accepted Answer · 2020-10-30 10:23:31Z

It's fine for your test to use field injection as the Test itself is not part of your domain; the test won't be part of your application context.

Also

You don't want to use SpringBootTest to test a controller, because that will wire ALL beans which can be way too heavy and time-consuming. Instead, you probably only want to create your controller and it's dependencies.

So your best option is to use @WebMvcTest which will only create the beans required for testing the specified controller.

@ExtendWith(SpringExtension.class) @WebMvcTest(controllers = PersonController.class) class PersonControllerTest { @Autowired private MockMvc mockMvc; @Test public void greetingShouldReturnDefaultMessage() throws Exception { mockMvc.perform(get("/cvtech/Persons")) .andExpect(status().isOk()) .andExpect(content().string(contains("content"))); } }

Note that @WebMvcTest will search for a class annotated with @SpringBootConfiguration as it's default configuration. If it does not find it, or you want to manually specify some configuration classes, also annotate the test with @ContextConfiguration.

Also, as a sidenote, when using TestRestTemplate, you don't need to specify host and port. Just call restTemplate.getForObject("/cvtech/persons", String.class)); Same when using MockMvc or WebTestClient.

Collectives™ on Stack Overflow

Spring Boot unit test constructor injection

2 Answers 2

Comments

Comments

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Related