[beta-devin-ai-integration]

Summary

Adds a black-box HTTP characterization suite (characterization-tests, JUnit 4 / Java 8) that pins what the legacy estate does today, so score-service-boot can be checked for parity before cutover. The tests are skipped in the normal build. Run them with -Dcharacterization=true against running services. -Dscore.url switches the score-service under test, and -Dgroups=com.ukcredit.characterization.ScoreApi limits the run to the checks that go through score-service.

• Golden master: after scripts/db-reset.sh (seed 20241231), GET /score/{id}?asOf=2024-12-31 for all 256 seeded consumers is recorded in golden/score-uks3.json, and GET /creditfile/{id} for 100001–100016 in golden/creditfile-edge-cases.json. Regenerate with -Dgolden.record=true. Each run writes field-level diffs to target/characterization/<target>/*-golden-diff.json.
• One named test per quirk: StatusXCutoffTest, DisputeSlaTest, UtilisationRoundingTest, NameMatchingTest, AddressHistoryMergeTest, plus DisputeScoreFlowTest, which checks for DISPUTE_OPEN and DISPUTE_CLOSE rows in SCORE_HISTORY and restores its own state.
• Behaviour pinned as it is today, beyond what the docs say:
  • the SLA cutoff ignores seconds (17:30:59 still counts as same day);
  • an unknown region (NI) gets no bank holidays at all;
  • the maiden-name alias is not used for matching;
  • dispute-triggered rescoring uses the score service's current date, not 2024-12-31.
• .github/workflows/characterization.yml (plain GitHub Actions, pull_request → uk-credit-legacy): set up Java 8 → build → db-reset → run-all → suite. The matrix is legacy, plus boot when score-service-boot/ exists on the branch. The boot leg uses Java 21 and starts Boot on :8092 against the same Postgres (SPRING_PROFILES_ACTIVE=postgres, PORT, DB_*). It points dispute-service at Boot and runs the ScoreApi checks. Surefire reports and the parity report are uploaded as artifacts.
• characterization-tests/parity/parity_report.py builds docs/cutover/score-service-parity-report.md from two runs. Root causes, approved intentional changes and out-of-suite notes are recorded in docs/cutover/parity-findings.json.

Parity summary: legacy score-service vs score-service-boot

Candidate: #7 (devin/1792677011-score-service-boot3 @ 8e8b546). It was checked out locally without committing to it and run on JDK 21 against the same PostgreSQL 15 database. Each implementation got a fresh db-reset first.

Result	Checks	Consumer scores (golden master)
MATCHED	5	256
DIFFERED	0	0
INTENTIONAL CHANGE	0	0

Recommendation: GO, subject to sign-off from Engineering, QA, Risk/Model Governance and Platform. Changes that #7 declares intentional but this suite doesn't exercise are listed in the report for explicit acceptance: JSON error bodies instead of Jetty HTML, default port 9082, and the shared SCR_HIST_SEQ.

The Actions run on this PR covers only the legacy target, because score-service-boot/ isn't on this branch. The boot matrix leg runs automatically on PRs where both are present, for example #7 once this lands.

Link to Devin session: https://cognition.beta.devinenterprise.com/sessions/b69735ce58a04288bfdaa7bb3d35c858
Open in Devin Desktop: https://cognition.beta.devinenterprise.com/desktop/session/b69735ce58a04288bfdaa7bb3d35c858?variant=devin
Requested by: @sofiasepielli1

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[beta-devin-ai-integration]

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