Spring Boot Test for Application Testing

Source: Spring Boot Test for Application Testing

1. Overview of Spring Boot Test

Spring Boot Test is a part of the Spring Boot framework that simplifies the testing of Spring components. It offers several annotations and utilities to help you write comprehensive tests for your application. Some key features include:

Integration Testing: Test your application with a real Spring context.
Mocking: Mocking beans and services to test specific parts of your application.
Testing Configuration: Load application contexts and configurations for testing purposes.

2. Key Annotations and Utilities

2.1 @SpringBootTest

The @SpringBootTest annotation is used to create an application context and load it for testing. It is useful for integration testing where you need to test the full application context.

@SpringBootTest
public class ApplicationTests {

    @Test
    void contextLoads() {
    }
}

2.2 @MockBean

The @MockBean annotation allows you to add Mockito mocks to the Spring application context. This is useful for unit testing where you want to isolate the component being tested.

@SpringBootTest
public class ServiceTests {

    @MockBean
    private MyService myService;

    @Autowired
    private MyController myController;

    @Test
    void testService() {
        Mockito.when(myService.getData()).thenReturn("Mocked Data");
        String result = myController.getData();
        assertEquals("Mocked Data", result);
    }
}

2.3 @DataJpaTest

The @DataJpaTest annotation is used to test JPA repositories. It configures an in-memory database for testing and scans for JPA repositories.

@DataJpaTest
public class RepositoryTests {

    @Autowired
    private MyRepository myRepository;

    @Test
    void testRepository() {
        MyEntity entity = new MyEntity();
        entity.setName("Test");
        myRepository.save(entity);

        List<MyEntity> entities = myRepository.findAll();
        assertEquals(1, entities.size());
    }
}

2.4 @WebMvcTest

The @WebMvcTest annotation is used for testing Spring MVC controllers. It configures only the web layer and does not load the full application context.

@WebMvcTest(MyController.class)
public class ControllerTests {

    @Autowired
    private MockMvc mockMvc;

    @Test
    void testController() throws Exception {
        mockMvc.perform(get("/endpoint"))
               .andExpect(status().isOk())
               .andExpect(content().string("Hello World"));
    }
}

3. Demo: Testing a Simple Spring Boot Application

3.1 Create a Simple Spring Boot Application

Read more at : Spring Boot Test for Application Testing