tests/__init__.py keeps a run offline, its scratch under tmp/ and its
installer cache its own, but only discover -s tests -t . imported it.
discover tests ran with RETROBIOS_OFFLINE unset, scratch on the /tmp
tmpfs and the user's real installer cache, the setting in which e2e
fixtures had written into the shared .cache/large. Every test module now
imports the package first, and a test fails on a module that does not.
test_verify_listing.py took its line with the previous commit.
The test simulates a miscompute on a real held file. Since the
manifest hash cache is keyed by the expected sha1, a result another
test verified for the same file is a valid hit, and in a single
process run the simulated miscompute was never hashed. The class
starts from an empty cache.
Abdessamad Derraz