Writing Junit Test case for merging files in sftp server

Question

I am using apache commons VFS to connect to sftp server and write the content of files in /input directory into a single file in /output directory.The names of files in input directory is provided as a List. I am struggling to write Junit test case for it.My intention is that once the code gets executed, I will compare the contents of file in /input against content of file in /output

public void exportFile(List<String> fileNamesList){
for (String file : fileNamesList){
            try(FileObject fileObject= //getsFileObject
                OutputStream fileOutputStream= fileObject.resolveFile("/output/"+"exportfile.txt").getContent().getOutputStream(true);
            )
                                            fileObject.resolveFile("/input/"+file).getContent().getInputStream().transferTo(fileOutputStream);
    
            }
            }

I want to write Junit test case for the above. The below is my setup for test case

            @BeforeAll
                  static void setUpSftpServer() throws IOException {
                System.out.println("inside setup ssh");
                sshd= SshServer.setUpDefaultServer();
                    sshd.setPort(1234);
                    sshd.setKeyPairProvider(new SimpleGeneratorHostKeyProvider());
                    sshd.setPublickeyAuthenticator(AcceptAllPublickeyAuthenticator.INSTANCE);
                    sshd.setSubsystemFactories(Arrays.asList(new SftpSubsystemFactory()));
                    sshd.start();
            }
        
         @Test
            void exportFileTest() throws IOException, URISyntaxException {
        
                System.out.println("Inside exportFile test");
                FileObject fileObject=getFileObject();
                when(sftpConfiguration.connect()).thenReturn(fileObject);
                myobject.exportFile(Arrays.asList("a.txt"));
               String actualContent=fileObject.resolveFile("/input/a.txt").getContentContent().getString("UTF-8");
 String expectedContent=fileObject.resolveFile("/output/exportFile.txt").getContentContent().getString("UTF-8");
                assertTrue(actualContent.equals(expectedContent));
        
        
            }
    static FileObject getFileObject() throws URISyntaxException, FileSystemException {
            String userInfo = "uname" + ":" + "pwd";
            SftpFileSystemConfigBuilder sftpConfigBuilder = SftpFileSystemConfigBuilder.getInstance();
            FileSystemOptions options = new FileSystemOptions();
            IdentityProvider identityInfo = new IdentityInfo(new File("/fake/path/to/key"), "test".getBytes());
            sftpConfigBuilder.setIdentityProvider(options, identityInfo);
            URI uri=  new URI("sftp", userInfo, "127.0.0.1", Objects.requireNonNullElse(1234, -1), null, null, null);
           FileObject fileObject= VFS.getManager().resolveFile(uri.toString(),options);
           System.out.println("creating file object complete");
           fileObject.resolveFile("/input").createFolder(); //create a folder in the path
           fileObject.resolveFile("/output").createFolder(); 
           //code  to create a file called a.txt inside /input and write the string "abc" to the file
            return  fileObject;
        }

But I am getting an exception like below

org.apache.commons.vfs2.FileSystemException: Unknown message with code "Could not get the user id of the current user (error code: -1)".

This exception I am getting at the line

FileObject fileObject= VFS.getManager().resolveFile(uri.toString(),options);

How do I write the unittest for this case correctly?

score 2 · Answer 1 · answered Nov 17 '22 at 20:11

This is caused by the SftpFileSystem failing to run the command id -u which doesn't exist on some SSH connections such as Windows OpenSSH. It runs this command when attempting to detect the exec channel. Resolve this by adding the following SFTP configuration:

sftpConfigBuilder.setDisableDetectExecChannel(options, true);

See here.

Writing Junit Test case for merging files in sftp server

1 Answers1