Connect to non-standard couchbase ports for integration testing - integration-testing

Question

I'm trying to set up automated integration-tests for a Spring Boot application that connects to couchbase. I want to test against a fresh containerised database using random available ports so that we don't need to worry about port collisions on developer machines or in continuous integration environments.
So far I've created a test that uses com.palantir.docker.compose.DockerComposeRule to spin up a couchbase docker image that exposes the standard ports on random available ports. However, org.springframework.boot.autoconfigure.couchbase.CouchbaseProperties doesn't expose any properties for ports.
I can see that org.springframework.data.couchbase.config.CouchbaseEnvironmentParser suggests that there is some way to set the ports. I haven't been able to work out how to use it though. Has anyone else been able to do this?
This is what my test looks like so far:
#Slf4j
#RunWith(SpringRunner.class)
#SpringBootTest
#Category(IntegrationTest.class)
public class BiscuitRepositoryIT {
private static final int COUCHBASE_PORT = 8091;
private static final String COUCHBASE_SERVICE = "couchbase";
#ClassRule
public static DockerComposeRule docker = DockerComposeRule.builder()
.file("src/test/resources/docker-compose-couchbase.yml")
.projectName(ProjectName.random())
.waitingForService(COUCHBASE_SERVICE, HealthChecks.toHaveAllPortsOpen())
.build();
#Autowired
private BiscuitRepositoryConfig config;
#Autowired
private BiscuitRepository biscuitRepository;
#BeforeClass
public static void initialize() {
DockerPort couchbase = docker.containers()
.container(COUCHBASE_SERVICE)
.port(COUCHBASE_PORT);
log.info("couchbase ports: {}", couchbase);
// TODO update integration-test properties file with the ports
// before the spring context starts.
}
#After
public void tearDown() throws Exception {
biscuitRepository.deleteAll();
}
#Test
public void insertBiscuit() throws Exception {
Biscuit digestive = Biscuit.builder().name("digestive").manufacturer("biscuitCorp").build();
Biscuit persistedBiscuit = biscuitRepository.save(digestive);
assertThat(persistedBiscuit).isEqualToIgnoringGivenFields(digestive, "id", "version");
}
}