Fix tests

[Quincunx271]

Fixes #3 and fixes #8 , along with some stuff which were necessary.

Some comments:

• This fix for #8 is not the best code. It literally copies code from _pf_auto into a new function. Ideally, this new function would share code with _pf_auto rather than copy-paste it.
• The ignored file is called ignore_in_diff. I don't have a preference for the name
• The ignored file is ignored in both the expected case and actual case. It might be better to only ignore it in the expected case, just in case the actual generated directories include the ignored file.

[vector-of-bool]

LGTM, other than the one comment.