[SSSD] [sssd PR#388][comment] IDMAP: add a unit test

[sumit-bose]

  URL: https://github.com/SSSD/sssd/pull/388
Title: #388: IDMAP: add a unit test

sumit-bose commented:
"""
retest this, please
"""

See the full comment at https://github.com/SSSD/sssd/pull/388#issuecomment-330789627