Springboot test fails to autowire TestRestTemplate when using junit5

I am using springboot version 2.2.2.RELEASE.

I am trying to add tests using junit5, this is how it is set up in build.gradle:

testImplementation('org.springframework.boot:spring-boot-starter-test') {
    exclude group: 'junit', module: 'junit'
}
testImplementation "org.junit.jupiter:junit-jupiter-api:5.5.2"
testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:5.5.2"

Here is my test class:

//@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment= SpringBootTest.WebEnvironment.RANDOM_PORT, classes = UserServiceApplication.class)
@ActiveProfiles("it")
public class UserControllerIntegrationTest {
    @Autowired
    private TestRestTemplate testRestTemplate;

}

The problem is that restRestTemplate is null. The only way it works is when using:

@RunWith（SpringRunner.class）

However, as I understand it, this is junit4 support, right?

I am using the deprecated TestRestTemplate (org.springframework.boot.test.web.client.TestRestTemplate).

I also tried adding the following, but that didn't work either:

@ExtendWith（SpringExtension.class）

What am I missing?

thanks.