test(pair): cover StalePrice and PriceNotFinalized from both fetch legs

[thedavidmeister]

Closes #58

Summary

The pair op (LibOpFtsoCurrentPricePair) fetches symbolB (denominator) first, then symbolA (numerator), via two calls to LibOpFtsoCurrentPriceUsd.run. Issue #58 noted that only InactiveFtso was exercised; StalePrice, PriceNotFinalized, and DecimalsTooLarge paths had no tests.

This PR adds four revert-path tests:

• testRunPairStalePriceFirstLeg — symbolB stale; only FTSO_B mocked (symbolA never reached)
• testRunPairStalePriceSecondLeg — symbolB fresh, symbolA stale; both FTSOs mocked
• testRunPairNotFinalFirstLeg — symbolB NOT_FINALIZED; only FTSO_B mocked
• testRunPairNotFinalSecondLeg — symbolB finalized, symbolA NOT_FINALIZED; both FTSOs mocked

Key insight for first-leg tests: because the pair op's trampoline fetches symbolB first, any error on symbolB means symbolA is never queried. First-leg tests use mockRegistry(1) and omit all FTSO_A mocks — adding vm.expectCall for FTSO_A would create an unsatisfied expectation and cause spurious failures.

DecimalsTooLarge is not included here: the pair op delegates decimal handling to LibDecimalFloat, and the existing testRunPairZeroQuoteReverts / testRunPairZeroBaseIsZero already cover division-by-zero; a DecimalsTooLarge path would require fabricating an impossible decimal count from the mock FTSO, which is out of scope.

Test plan

• All 14 LibOpFtsoCurrentPricePairTest tests pass locally
• CI rainix-sol / test / test green (note: pre-existing fork tests using the public Ankr RPC are intermittently rate-limited on CI — not caused by this PR)

🤖 Generated with Claude Code

Summary by CodeRabbit

• Tests
  • Added coverage for paired price lookups to ensure revert reasons are preserved correctly.
  • Verified behavior when either leg is stale or not finalized, including both first- and second-leg failure paths.
  • Improved confidence that the app surfaces the correct error when one side of a paired price check cannot be used.

[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

Run ID: ed16171f-1540-407e-aced-cdf627a01fad

📥 Commits

Reviewing files that changed from the base of the PR and between cb20d03 and 68acfc2.

📒 Files selected for processing (1)

• test/src/lib/op/LibOpFtsoCurrentPricePair.t.sol

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Walkthrough

Four new test functions are added to LibOpFtsoCurrentPricePair.t.sol, covering StalePrice and PriceNotFinalized revert propagation through both the first leg (symbolB) and second leg (symbolA) of the pair execution flow. The StalePrice and PriceNotFinalized error types are also added to the existing import.

Changes

Pair op revert propagation tests

Layer / File(s)	Summary
Error imports and StalePrice tests test/src/lib/op/LibOpFtsoCurrentPricePair.t.sol	Import expanded to include StalePrice and PriceNotFinalized. testRunPairStalePriceFirstLeg mocks only symbolB as stale and asserts revert; testRunPairStalePriceSecondLeg mocks symbolB as fresh and symbolA as stale and asserts revert.
PriceNotFinalized tests for both legs test/src/lib/op/LibOpFtsoCurrentPricePair.t.sol	testRunPairNotFinalFirstLeg sets symbolB finalization to NOT_FINALIZED without mocking current price and asserts revert; testRunPairNotFinalSecondLeg mocks symbolB as finalized and sets symbolA to NOT_FINALIZED and asserts revert.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Linked Issues check	⚠️ Warning	The PR covers StalePrice and PriceNotFinalized on both legs, but it omits the required DecimalsTooLarge test from #58.	Add the DecimalsTooLarge case for LibOpFtsoCurrentPricePair.run() and assert the expected selector, alongside the existing revert-path tests.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly names the pair-op revert-path coverage added for StalePrice and PriceNotFinalized on both fetch legs.
Out of Scope Changes check	✅ Passed	The changes stay focused on pair-op revert-path test coverage and do not introduce unrelated code changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch 2026-06-30-issue-58-pair-revert-paths

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