Broken Python unit test load_save_test.py need help to finish the fix

Hello,

In January I was working on the python units tests and making them more 
pythonic as per the easy hack at 
https://bugs.documentfoundation.org/show_bug.cgi?id=97361.

I found a broken and disabled test while doing so - load_save_test.py. I 
have started an attempt to fix it, and fixed several issues, but I 
reached a roadblock when my knowledge of pyUNO and UNO wasn't enough to 
finish it. The results of the work so far are at 
https://gerrit.libreoffice.org/#/c/66275/.#

What seems to happen is the test segfaults when loading a file, 
seemingly regardless of what that file is - see the comment at line 91.

Could anyone help me figure out what is going on here so we can fix this 
test?

Thanks,

Hamish