Add direct tests for payment pricing

[stefan-burke]

What changed

Added a standalone test file for payment pricing (test/features/api/payment-processing/pricing.test.ts) that calls the real production code directly — no server, no Stripe, no database.

The production file src/features/api/payment-processing/pricing.ts got one small change: checkoutIntentForSession now reuses the existing contactFields helper (from src/shared/db/attendees/pii.ts) instead of copying the contact fields by hand. This is the same helper the final split branch uses, and it stays behaviour-preserving because:

• the helper returns the same five fields (address, email, name, phone, special_instructions) the old inline copy did;
• contactFields already has current production callers (committed-entries.ts, attendees/create.ts, attendees/pii.ts);
• no refund behavior, orderLineTotal, or staged-checkout types were touched.

Why

The pricing module is the last gate before a signed order is honoured: it re-prices the order and decides whether today's prices still match what the buyer was charged. That logic (contact fields, signed totals, item totals, deposits, modifiers, pay-more bounds, and the failure paths that refund when a price drifted mid-checkout) deserves a fast, focused unit suite instead of only being exercised through full webhook integration tests.

What the tests cover

• Contact fields: every signed field (name, email, phone, address, special instructions) is copied onto the checkout intent, including package group, day count, and reservation data when present — and omitted when absent.
• Package vs group edge: a k: "p" line becomes a packageGroupId, a k: "g" line does not.
• Item totals (orderLineTotal): split deposit lines are summed, modifier extras are excluded.
• Per-item totals (paidByItem): split lines for the same item add up; two booking paths for one listing stay separate.
• Signed totals (paidPricingRefund): an unchanged fixed-price order passes; a deposit is accepted while the full item price is still checked; an unchanged modifier total passes; a changed re-derived total refunds with the exact detail string.
• Failure boundaries: a package member no longer in its package fails closed; fixed-price mismatches both below and above; pay-more boundaries (min and max) pass and out-of-range values refund; a free item whose current price turned positive refunds.
• Mutation testing: 100% kill rate (34/34 killed, one ?? → || fallback recorded as a proven equivalent).

Verification

• deno task test:files test/features/api/payment-processing/pricing.test.ts — 21 tests pass
• deno task test:quality-audit — no findings in the new file
• deno task mutation src/features/api/payment-processing/pricing.ts test/features/api/payment-processing/pricing.test.ts — 100% (34 killed, 1 suppressed equivalent)
• deno task precommit — green

Notes

• Production code changed (one helper reuse in pricing.ts), behaviour-preserving.
• No refund behavior, orderLineTotal, or staged types were changed.
• No PR created — this IS the PR.

Summary by CodeRabbit

• Improvements

  • Checkout intents now consistently include available contact information and signed pricing details.
  • Payment totals are calculated more reliably across deposits, modifiers, packages, and multiple charged lines.
  • Refund validation now better handles pricing changes and prevents refunds when finalized totals no longer match.

• Tests

  • Expanded coverage for checkout details, payment aggregation, package pricing, deposits, modifiers, and refund scenarios.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 1afeefe3-eacd-4a30-a4db-17540acf275e

📥 Commits

Reviewing files that changed from the base of the PR and between e6d32a7 and e002000.

📒 Files selected for processing (3)

• scripts/mutation/equivalent-mutants.txt
• src/features/api/payment-processing/pricing.ts
• test/features/api/payment-processing/pricing.test.ts

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📝 Walkthrough

Walkthrough

checkoutIntentForSession now uses shared contact-field extraction, while payment totals and refund validation receive extensive test coverage. A mutation-equivalence entry documents the charged-total fallback behavior.

Changes

Payment pricing behavior

Layer / File(s)	Summary
Checkout intent contact propagation src/features/api/payment-processing/pricing.ts, test/features/api/payment-processing/pricing.test.ts	Checkout intent construction spreads shared contact fields, and tests cover contact serialization, signed pricing, optional fields, and group-edge handling.
Payment totals and refund validation test/features/api/payment-processing/pricing.test.ts, scripts/mutation/equivalent-mutants.txt	Tests cover charged-line aggregation, package and standalone totals, accepted and rejected refund scenarios, and a documented equivalent `?? →

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

• chobbledotcom/tickets#1692: Directly introduced related checkoutIntentForSession contact-field behavior.
• chobbledotcom/tickets#1898: Audits the equivalent-mutant catalog touched by this change.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: adding direct tests for payment pricing.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch split/payment-pricing-tests

✨ Simplify code

• Create PR with simplified code
• Commit simplified code in branch split/payment-pricing-tests

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