Use Session collection for testing libsecret backend

[mitya57]

This is something I needed to apply to make the tests pass for Debian package.

The Session collection is not documented in the specification and is specific to GNOME Keyring, but we do the same for testing SecretStorage backend:

keyring/tests/backends/test_SecretService.py

Line 21 in fb37652

keyring.preferred_collection = '/org/freedesktop/secrets/collection/session'

The login collection is not available in a clean environment, which results in this error:

No such interface “org.freedesktop.Secret.Collection” on object at path /org/freedesktop/secrets/collection/login

[jaraco]

I can't tell - are these preferred_collection attributes the same? Why do the tests set them to different values (/org/freedesktop/secrets/collection/session and session)?

[mitya57]

@jaraco libsecret accepts only the alias, while SecretStorage accepts the full path.

Quoting libsecret documentation:

If collection is NULL, then the default collection will be used. Use SECRET_COLLECTION_SESSION to store the password in the session collection, which doesn't get stored across login sessions.

Where SECRET_COLLECTION_SESSION is defined as "session".

Maybe it would be better to use Secret.COLLECTION_SESSION, but I wanted to avoid an extra import in tests.

[mitya57]

How it works can be seen here:
https://salsa.debian.org/python-team/packages/python-keyring/-/commits/debian/master/

In particular, a job without this patch failed and a job with this patch passed.