export files=`ls /home/tests/`
 complete -o filenames -W "${files}" xtest

_xtest ()   {                .
      local cur
      local files=`ls /home/tests`
      COMPREPLY=()     cur=${COMP_WORDS[COMP_CWORD]}

      #case "$cur" in

        COMPREPLY=( $(compgen -W "${files}" -- ${cur}) )
    #  esac
      return 0
    }

    complete -F _xtest -o filenames xtest