Make postgres_cluster and config_psql_dos fixtures configurable

[sphuber]

The postgres_cluster and config_psql_dos fixtures are made available publicly in order to help plugin packages with unit testing. Particularly, these fixtures should make it easy to generate test profiles using the core.psql_dos storage plugin, generating the postgres database in a test cluster that is created on-the-fly.

The problem was that the interface did not actually allow to configure anything, such as the database name, but this was hardcoded. This would work fine in case it was used just once, but the fixtures could not be used to create a second profile, as the database name would already exist.

The postgres_cluster fixture is turned into a factory, allowing the database name, username and password to be customized. The unbound method create_database is added to the PGTest instance that it returns to easily create a new database.

The config_psql_dos fixture now actually forwards the relevant part of the custom_configuration to the postgres_cluster.create_database call.

Finally, the aiida_profile_factory fixture factory now makes the custom_configuration argument actually optional, as originally was intended.

[sphuber]

@unkcpz would you care to have a look please?

[unkcpz]

Thanks @sphuber. The changes looks all good.

[unkcpz]

When I review the PR, it reminds me a warning exception in AiiDAlab test, I can confirm it comes from the pytest_fixture and from aiida_profile. Maybe not related to the PR but I assume you have expertise to spot why it happened:

It is a dummy test in aiidalab-widgets-base only load the aiida.manage.tests.pytest_fixtures. It appears after we turn on pytest option of show warning as error.

After I comment out the aiida_profile fixture, this warning disappeared.

tests/test_a.py::test_a Exception ignored in: <_io.FileIO name=6 mode='rb' closefd=True>
Traceback (most recent call last):
  File "/home/jyu/micromamba/envs/aiidalab-dev/lib/python3.9/site-packages/_pytest/unraisableexception.py", line 59, in __exit__
    del self.unraisable
ResourceWarning: unclosed file <_io.BufferedReader name=6>
Exception ignored in: <_io.FileIO name=8 mode='rb' closefd=True>
Traceback (most recent call last):
  File "/home/jyu/micromamba/envs/aiidalab-dev/lib/python3.9/site-packages/_pytest/unraisableexception.py", line 59, in __exit__
    del self.unraisable
ResourceWarning: unclosed file <_io.BufferedReader name=8>

[sphuber]

When I review the PR, it reminds me a warning exception in AiiDAlab test, I can confirm it comes from the pytest_fixture and from aiida_profile. Maybe not related to the PR but I assume you have expertise to spot why it happened

I have seen these warnings before as well, but haven't had the time to investigate it yet. The aiida_profile fixture does depend on some other fixtures that create temporary files, for example for the config.json it creates, and these may not be properly cleaned up. But I would have to look in depth. Don't have an immediate hunch now what it might be.