Add baseline tests for Post::get_type()

[obenland]

Allows us to make changes with more confidence in the future.

Fixes #

Proposed changes:

*

Other information:

• [ ] Have you written new tests for your changes, if applicable?

Testing instructions:

• Go to '..'

[obenland]

@pfefferle I asked Claude.ai to create some unit tests for the get_type() method as it's written in trunk, so we can compare future changes with those outcomes.

It currently fails for posts without a post format (test_get_type_handles_missing_post_format), probably because of a wrong assumption? Posts with a title, more than 400 char content and no post format should be considered Articles, yes?

[pfefferle]

@obenland I would say so, yes.

[obenland]

Yeah I got a phpcs error for the filename without the pre-pended class-. I'll do a follow up.