Spring Integration FakeFtpServer Example

For people in a hurry, get the latest code and the steps in GitHub.

To run the junit test, run “mvn test” and understand the test flow.

Introduction: FakeFtpServer

In this Spring Integration FakeFtpServer example, I will demonstrate using Spring FakeFtpServer to JUnit test a Spring Integration flow. This is an interesting topic, there are a few articles like Unit testing file transfers, which give some insight on this topic.

In this blog, we will test a Spring Integration flow which checks for a list of files, applies a splitter to separate each file, and starts downloading them into a local location. Once the download is complete, it will delete the files on the FTP server. In my next blog, I will show how to do JUnit testing of Spring Integration flow with SFTP Server.

Spring Integration Flow

In order to use FakeFtpServer, we need to have Maven dependency as below:

<dependency>
<groupId>org.mockftpserver</groupId>
<artifactId>MockFtpServer</artifactId>
<version>2.3</version>
<scope>test</scope>
</dependency>

The first step to this is to create a FakeFtpServer before every test runs as below:

@Before
public void setUp() throws Exception {
fakeFtpServer = new FakeFtpServer();
fakeFtpServer.setServerControlPort(9999); // use any free port
FileSystem fileSystem = new UnixFakeFileSystem();
fileSystem.add(new FileEntry(FILE, CONTENTS));
fakeFtpServer.setFileSystem(fileSystem);
UserAccount userAccount = new UserAccount("user", "password", HOME_DIR);
fakeFtpServer.addUserAccount(userAccount);
fakeFtpServer.start();
}

@After
public void tearDown() throws Exception {
fakeFtpServer.stop();
}

Finally, run the JUnit test case as below:

@Autowired
private FileDownloadUtil downloadUtil;
@Test
public void testFtpDownload() throws Exception {
File file = new File("src/test/resources/output");
delete(file);
FTPClient client = new FTPClient();
client.connect("localhost", 9999);
client.login("user", "password");
String files[] = client.listNames("/dir");
client.help();
logger.debug("Before delete" + files[0]);
assertEquals(1, files.length);
downloadUtil.downloadFilesFromRemoteDirectory();
logger.debug("After delete");
files = client.listNames("/dir");
client.help();
assertEquals(0, files.length);
assertEquals(1, file.list().length);
}

I hope this blog helped.