Use script output folder for unit test outputs

[amhanson9]

Currently, unit tests are saving to the tests folder in the script repo, which is the current working directory (at least in PyCharm). In the real script, content is in the script output directory.

Could change the current directory to the script output directory in order to be closer to the real script function and to make deletion easier at the end (delete script output directory and all its contents instead of each seed_id folder, plus seeds_log.csv and completeness.csv). But the tests are also probably good enough as is.