test_jar_id_defaults_to_live_and_reports_explicit_path's reference hash is computed by calling
hash256 itself (needed so it doesn't call the Linux-crashing bare shasum directly). That made
subject and reference the same instrument: they agree no matter which algorithm hash256 actually
runs, so a mutation swapping both of hash256's arms for the wrong algorithm was invisible to the
suite.
Adds test_hash256_computes_a_real_sha256, pinned against the published SHA-256 test vector for the
3-byte input "abc" (ba7816bf8f01...), written as a literal constant rather than computed by any
hasher at test time. Verified the constant myself both ways (sha256sum and shasum -a 256) before
writing it in.
Dai Ha
b8182c96c2