Tests/SFTP: add unit test
Tests/SFTP: add unit test

paragonie-scott/phpseclib,metaclassing/phpseclib,kenichiii/phpseclib,metaclassing/phpseclib,danog/phpseclib,kenichiii/phpseclib,terrafrost/phpseclib,splitice/phpseclib,danog/phpseclib,splitice/phpseclib,phpseclib/phpseclib,paragonie-scott/phpseclib,thaigialai1987/phpseclib,thaigialai1987/phpseclib