Exercise the cache's read path in the equivalence test
What the developer wrote
Authored by kdmukai
Exercise the cache's read path in the equivalence test
Both psbts carried a single change output, so every derivation was a
first-time miss and the cached run only ever wrote to the cache. A
wrong value returned on a hit would have gone unnoticed. Carrying the
change output twice makes the second traversal read back what the
first one cached.
What changed, and why it matters
This commit only changes a test file. It strengthens an existing test so that it actually exercises the read path of a caching mechanism, rather than only the write path. There is no change to production code, no fix for a vulnerability, and no indication of a security issue being patched.
No action needed. This is a benign test-only improvement. Reviewers may optionally verify that the production cache implementation has independent coverage for read-path correctness.
Security signals we found
No strong security signals were identified.
Evidence from the diff
The change is in tests/test_psbt_parser.py. The test_cache_does_not_change_parse_output test builds a PSBT and appends a duplicate change output so that the second traversal exercises the cache’s read path. Previously, only one change output was appended, meaning every derivation was a cache miss and the test only verified that caching did not change behavior on first access. This is a test-coverage improvement, not a code fix.
Changed components
tests/test_psbt_parser.pyInspect captured patch +5 / −1
### tests/test_psbt_parser.py
@@ -658,9 +658,13 @@ def test_cache_does_not_change_parse_output(self):
each cosigner's account xpub.
"""
def build_psbt(input_base64: str, change_hex: str) -> PSBT:
- # A fresh psbt for each parse: the base psbt plus its change output
+ # A fresh psbt for each parse: the base psbt plus its change output, twice.
psbt = PSBT.parse(a2b_base64(input_base64))
psbt.outputs.append(create_output(change_hex, 10_000))
+
+ # Add a duplicate output to ensure that the cache yields some hits; the second
+ # output will traverse the same levels the first one just cached.
+ psbt.outputs.append(create_output(change_hex, 10_000))
return psbt
def assert_cache_makes_no_difference(input_base64: str, change_hex: str):Why this scored 12/100
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