How to test spring integration channels

I have some differents channels to handle files coming from FTP. Everything is working and now, I have to write tests. The entrypoint is an InboundChannelAdapter to take all files from a ftp, handle them, and put the data into Elasticsearch.

I have set my Index in the setUp() but I don't understand how to launch my feed to perform my tests.

My test class is prefixed with these annotations :

@RunWith(SpringJUnit4ClassRunner.class)
@ActiveProfiles("profile")
@TestPropertySource({ "/application.properties", "/application-profile.properties" })
@ContextConfiguration(classes = { 
// all classes needed
 })
public class MyTest {
    // treatment
}

So, there is a way to launch my channels and handle files coming from a mocked ftp (done) to perform the ingestion feed ?