Use Spring Data random (embedded) Mongo port with NoSQL JUnit @Rule

I'm currently trying to write an Integration test class which uses Spring Data Mongo repositories. I use an embedded Mongo instance provided by the de.flapdoodle.embed.mongo dependency. Spring Data documentation specifies that we only have to put this dependency in the project and the EmbedMongoAutoConfiguration takes care of the rest.

For now, that's ok, and setting the port to 0 makes the auto configuration process to find a free port to launch the mongo instance on.

This feature is necessary for me to avoid collision with other tests (which are run on a Jenkins CI server along with other project of my company).

The problem comes now, I want to be able to inject some test data from some external file before each of my test method run. I found out that NoSQL Unit can do this with a simple method annotation and a JUnit @Rule.

Here is an example:

@Value("${local.mongo.port}")
private int mongoPort; // <- still 0 a the time the Rule below is created.

@Rule
public MongoDbRule managedMongoDb = new MongoDbRule(MongoDbConfigurationBuilder.mongoDb().databaseName("myAwesomeDb").port(mongoPort).build());

@Test
@UsingDataSet(locations = "testdata.json", loadStrategy = LoadStrategyEnum.CLEAN_INSERT)
public void testMyData() {
   // ...
}

My problem is that, the @Rule needs the Mongo port in its builder to instantiate the underlying MongoClient, but at the time the @Rule is instantiated, the Spring context is not fully initialized and the EmbeddedMongoAutoConfiguration has not published the port yet.

So my question is, is there anyone who has ever used the Embedded Mongo feature with NoSQL Unit, and is there any way to, for example create the @Rule after the Spring context is initialized ?

I was wondering if finding the free port myself (in a static way), setting it to the @Rule and then tell the EmbeddedMongoAutoConfiguration to use it by overriding the IMongodConfig bean was a good idea ? or is there a "simpler" way ?

Note: I just saw that flapdoodle library provides a class and a static method to find a free server port and its used by Spring like this:

Network.getFreeServerPort(getHost()), Network.localhostIsIPv6()))

Thanks everyone in advance!

EDIT: I tried the solution I talked just above, and it seems to work, though I still think it's a bit "verbose" and dirty.

private static final Logger log = LoggerFactory.getLogger(MyAwesomeIT.class);
private static int mongoPort;
static {
    try {
        mongoPort = Network.getFreeServerPort();
    } catch (IOException e) {
        log.error("Error while trying to find a free port for Mongo", e);
        mongoPort = -1; // test should then not work
    }
}

@Rule
public MongoDbRule managedMongoDb = new MongoDbRule(MongoDbConfigurationBuilder.mongoDb().databaseName("myAwesomeDb").port(mongoPort).build());

then in the associated configuration class :

@Configuration
@EnableAutoConfiguration
@EnableMongoRepositories
@EnableConfigurationProperties(MongoProperties.class)
static class ContextConfiguration {
    @Autowired
    private MongoProperties mongoProperties;

    @PostConstruct
    public void init() {
        // Here, I override the port property
        mongoProperties.setPort(mongoPort);
    }
}