Spring Boot @WebMvcTest vs @SpringBootTest

I have a simple health controller defined as follows:

@RestController
@RequestMapping("/admin")
public class AdminController {

    @Value("${spring.application.name}")
    String serviceName;

    @GetMapping("/health")
    String getHealth() {
        return serviceName + " up and running";
    }
}

And the test class to test it:

@WebMvcTest(RedisController.class)
class AdminControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @Test
    public void healthShouldReturnDefaultMessage() throws Exception {
        this.mockMvc.perform(get("/admin/health"))
                .andDo(print())
                .andExpect(status().isOk())
                .andExpect(content().string(containsString("live-data-service up and running")));
    }
}

When running the test, I'm getting the below error:

***************************
APPLICATION FAILED TO START
***************************

Description:

Field configuration in com.XXXX.LiveDataServiceApplication required a bean of type 'com.XXXXX.AppConfiguration' that could not be found.

The injection point has the following annotations:
	- @org.springframework.beans.factory.annotation.Autowired(required=true)


Action:

Consider defining a bean of type 'com.XXXX.AppConfiguration' in your configuration.

Here is AppConfiguration.java defined in the same package as the main spring boot app class:

@Configuration
@EnableConfigurationProperties
@ConfigurationProperties
public class AppConfiguration {

    @Value("${redis.host}")
    private String redisHost;

    @Value("${redis.port}")
    private int redisPort;

    @Value("${redis.password:}")
    private String redisPassword;
...
// getters and setters come here

Main class:

@SpringBootApplication
public class LiveDataServiceApplication {

    @Autowired
    private AppConfiguration configuration;

    public static void main(String[] args) {
        SpringApplication.run(LiveDataServiceApplication.class, args);
    }

    @Bean
    public RedisConnectionFactory redisConnectionFactory() {
        RedisStandaloneConfiguration redisConfiguration = new RedisStandaloneConfiguration(configuration.getRedisHost(), configuration.getRedisPort());
        redisConfiguration.setPassword(configuration.getRedisPassword());
        return new LettuceConnectionFactory(redisConfiguration);
    }
}

If I modify the annotation in the test class as follows, the test pass:

@SpringBootTest
@AutoConfigureMockMvc
class AdminControllerTest {
....

What am I missing?

You should understand the usage of @WebMvcTest and @SpringBootTest

@WebMvcTest : annotation is only to instantiates only the web layer rather than the whole context, so all dependencies in controller class should be mocked, you can look at the documentation

>Spring Boot instantiates only the web layer rather than the whole context. In an application with multiple controllers, you can even ask for only one to be instantiated by using, for example, @WebMvcTest(HomeController.class).

>We use @MockBean to create and inject a mock for the GreetingService (if you do not do so, the application context cannot start)

SpringBootTest : Spring boot test annotation actual load the application context for test environment

>The @SpringBootTest annotation tells Spring Boot to look for a main configuration class (one with @SpringBootApplication, for instance) and use that to start a Spring application context.

Define all properties in src/test/resource/application.file
example to use junit 5 for rest layer:

@ExtendWith(MockitoExtension.class)
public class RestTest {

	
	@InjectMocks
	private RestClass  restClass;
	
	
	
	private MockMvc mockMvc;
	
	@BeforeEach
	public void init() throws Exception {
		MockitoAnnotations.initMocks(this);
		mockMvc = MockMvcBuilders.standaloneSetup(restClass).build();
	}
	
	@Test
	public void test() throws Exception {
		String url = "/url";
		ResultActions resultActions = mockMvc.perform(get(url));
		resultActions.andExpect(status().isOk());

	}
	}