Title: #959: tests: fix race confition in enumeration tests
This is a little bit awkward, but as I am not original author of those patches I think it
makes some sense: here is my ACK for those patches :-)
Still as I combined two patches it definitely needs another review to get accepted.
@mzidek-rh, could you please take a look as you already reviewed #956?
See the full comment at https://github.com/SSSD/sssd/pull/959#issuecomment-563250774