test: Fix sitemap test base directory.

[projectgus]

When run with "pdm run invoke test", the CWD is the root of the sitemap plugin (at least on Linux). However, the test case expects to find content in the same directory as the test source file.

Closes #36.

[projectgus]

It looks like when the "CONTENT" directory didn't exist (it was /path/to/sitemap/test_data not /path/to/sitemap/pelican/plugins/sitemap/test_data), Pelican loaded content from its own tests/ directory which I think is why the errors relate to first-article.html generated from here - although I'm not sure why it loaded this file at all, or why it seems to have loaded it twice?

So I don't exactly understand why that behaviour appears, it might be a secondary bug that masked this one?

[justinmayer]

Many thanks, Angus! Interesting… I'm not sure about the questions you raised, but it seems that you have found a solution that will suit our needs for the moment.

I took the liberty of replacing the __file__ reference with the importlib.resources.files Python 3.9+ API.

Thanks again for your help. Much appreciated! 🏅

[projectgus]

I took the liberty of replacing the __file__ reference with the importlib.resources.files Python 3.9+ API.

Oh nice, I did catch myself wondering if there was a more modern way to get this information - and now I know what it is!