Add tests for evals

[anthonyduong9]

Description

Adds unit tests for all_loadable_saes() and get_saes_from_regex(), and another test for run_evals(). There's no coverage for the first two functions, and there's no coverage for single_head_replacement_hook() and single_head_zero_ablate_hook() defined inside of the third function, at https://app.codecov.io/gh/jbloomAus/SAELens/blob/main/sae_lens%2Fevals.py.

Fixes #82

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have not rewritten tests relating to key interfaces which would affect backward compatibility

You have tested formatting, typing and unit tests (acceptance tests not currently in use)

• I have run make check-ci to check format and linting. (you can run make format to format code if needed.)

Performance Check.

If you have implemented a training change, please indicate precisely how performance changes with respect to the following metrics:

• L0
• CE Loss
• MSE Loss
• Feature Dashboard Interpretability

Please links to wandb dashboards with a control and test group.

[chanind]

👍 Thanks for adding these!