[BUG] Running `pytest` errors on regression test that runs `git log`

[timothy-nunn]

Running pytest (or replicable with less tests by running pytest -k "test_main_int or large_tokamak") causes an error in the regression tests (git log errors with 128). This is being caused by the directory of the test being run in being an old tmp test directory, hence the following error:

----------------------------------------------------------------------------------------------- Captured stdout setup ------------------------------------------------------------------------------------------------
/private/var/folders/2c/5k4t0wm94jxdmnqwdvn_h59r0000gq/T/pytest-of-timothynunn/pytest-45/test_vary_run0
----------------------------------------------------------------------------------------------- Captured stderr setup ------------------------------------------------------------------------------------------------
fatal: not a git repository (or any of the parent directories): .git