Can't get ${server.port} from application.yml in @SpringApplicationConfiguration annotated test

I get a -1 value returned when trying to get the server.port property from application.yml in a test context.

I do black box testing of a Spring-bot app. Here's a test case:

@SpringApplicationConfiguration(TestConfiguration.class)
public class StartupTest extends AbstractTestNGSpringContextTests implements EnvironmentAware {

    private static Logger logger = LoggerFactory.getLogger(StartupTest.class);

    @Value("${server.port}")
    private String port;

    @Value("${project.name}")
    private String name;

    private RelaxedPropertyResolver propertyResolver;

    @Override
    public void setEnvironment(Environment environment) {
        this.propertyResolver = new     RelaxedPropertyResolver(environment);
    }

    @Test
    public void isAppUpAndRunning() {
        logger.debug("port: " + port);
        logger.debug("name: " + name);
        logger.debug("value for project.name: " + propertyResolver.getProperty("project.name"));
        logger.debug("value for server.port: " + propertyResolver.getProperty("server.port"));
        logger.debug("value for server.servlet-path: " + propertyResolver.getProperty("server.servlet-path"));
    }
}

NB: TestConfiguration.class contains nothing but @Configuration

Output:

[DEBUG] com.project.StartupTest - Running with Spring Boot v1.3.3.RELEASE, Spring v4.2.5.RELEASE
[INFO] com.project.StartupTest - The following profiles are active: test
[INFO] com.project.StartupTest - Started StartupTest in 4.698 seconds (JVM running for 7.761)
[DEBUG] com.project.StartupTest - port: ${server.port}
[DEBUG] com.project.StartupTest - name: ${project.name}
[DEBUG] com.project.StartupTest - value for project.name: MyProject
[DEBUG] com.project.StartupTest - value for server.port: -1
[DEBUG] com.project.StartupTest - value for server.servlet-path: /

So there's actually 2 questions here:

• why can't I get the properties injected with the @Value annotation?
• why can I get all application.yml properties with a PropertyResolver but server.port ?

What I need ultimately is a convenient way to access all the application.yml properties in a 'classic' test (i.e. not a Spring integration test as I want to test the application as it is at runtime). I've tried using

@ContextConfiguration(classes = TestConfiguration.class, initializers = ConfigFileApplicationContextInitializer.class)

as well, but the problem remains the same.