Layup checking Sorcha cache for files when cache_dir is None in LayupObservatory.

[Little-Ryugu]

When initialising the LayupObservatory class and the cache_dir is None, Layup will use the local user's Sorcha cache for aux files.

This is because the function layup_furnish_spicepy uses the Sorcha function sorcha.ephemeris.simulation_setup.furnish_spiceypy , which defaults to the Sorcha cache when cache_dir is none:

layup/src/layup/utilities/data_processing_utilities.py

Lines 347 to 352 in bec2747

	def layup_furnish_spiceypy(cache_dir):
	"""A simple wrapper to furnish spiceypy kernels."""
	# A simple class to mimic the arguments processed by Sorcha's observatory class
	config = LayupConfigs()
	furnish_spiceypy(FakeSorchaArgs(cache_dir), config.auxiliary)

layup/src/layup/utilities/data_processing_utilities.py

Lines 354 to 378 in bec2747

	class LayupObservatory(SorchaObservatory):
	"""
	A wrapper around Sorcha's Observatory class to provide additional functionality for Layup.
	"""
	def __init__(self, cache_dir=None):
	"""Create an instance of the LayupObservatory class.
	Parameters
	----------
	cache_dir : str, optional
	The location of the cache directory containing the bootstrapped files.
	If the files or cache is not present, the files will be downloaded, by default None
	"""
	# Get Layup configs
	config = LayupConfigs()
	# Kept so space-observatory Horizons lookups land their persistent
	# (naif_id, jd) -> state cache under the same cache directory.
	self.cache_dir = cache_dir
	# Furnish the spiceypy kernels
	layup_furnish_spiceypy(cache_dir)

This resulted in a failed unit test for me locally, as my Sorcha cache didn't have up-to-date Obs codes (unit tests worked after Sorcha bootstrap was used).

Both orbitfit and predict that use this class specify the cache_dir, so no issues in the main code, only unit tests that don't specify cache_dir can lead to this error.

Changing the default from None to the local layup cache dir: cache_dir = str(pooch.os_cache("layup")) should fix this.