println commonPath('/',
    '/home/user1/tmp/coverage/test',
    '/home/user1/tmp/covert/operator',
    '/home/user1/tmp/coven/members')

println commonPath('/',
    '/home/user1/tmp/coverage/test',
    '/home/user1/tmp/covert/test',
    '/home/user1/tmp/coven/test',
    '/home/user1/tmp/covers/test')