43 tests exercising one happy path and the major error paths per module (invalid regex pattern, oversize random::bytes, malformed JSON, bad base64, mixed-case hex round-trip, invalid UTF-8 in url::decode, etc.). Harness duplicates the pattern from sdk_contract.rs — each integration test file in this crate keeps its own; there is no tests/common/. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>