The NixOS manual documents that you can invoke every tests using
nix-build path/to/nixos/tests/test.nix
which was not the case for openldap since it is not autocallable, but
requires pkgs and system as arguments. Usually, make-test-pythons.nix
takes care of this if it is imported at the top-level, but since
openldap.nix contains multiple tests, this was not the case.
This is however easily fixed by:
* Adding default values for the pkgs and system arguments based on the
definition in make-test-python.nix
* Passing pkgs and system explicitly to make-test-python.nix to ensure
the pkgs and system values passed from all-tests.nix are used.
The old slapd.conf is deprecated. Replace with slapd.d, and use this
opportunity to write some structured settings.
Incidentally, this fixes the fact that openldap is reported up before
any checks have completed, by using forking mode.
