# Test — Settings Save Resilience & 2 s Error Budget

**Task**: AZ-477_test_settings_resilience
**Name**: Settings save 500 + network drop — `saving` flag reset + error surfaces ≤ 2 s
**Description**: Implement the 5 blackbox tests covering Settings save resilience: upstream 500, network drop, the 2-second error-surface deadline, and the try/finally state reset that prevents a stuck "saving…" indicator.
**Complexity**: 3 points
**Dependencies**: AZ-456_test_infrastructure
**Component**: 09_settings (Blackbox Tests)
**Tracker**: AZ-477
**Epic**: AZ-455

## Problem

Settings save has been observed to leave the `saving` flag set after an upstream failure (annotated in `src__features__settings__SettingsPage.md`). The user sees a forever-spinning button and the page becomes unusable. The contract: on ANY failure (HTTP error or network error), state resets within 2 s AND a user-visible error appears.

## Outcome

- 5 scenarios pass.

## Scope

### Included

| Scenario | Profile | Source file |
|----------|---------|-------------|
| FT-N-13 — Settings save with 500 response — `saving` flag reset; error surfaced | fast | blackbox-tests.md |
| FT-N-14 — Settings save with network failure — try/finally state reset | fast | blackbox-tests.md |
| NFT-PERF-09 — Settings save error surfaces within 2 s | fast | performance-tests.md |
| NFT-RES-05 — Settings save with upstream 500 — UI state recovers | fast | resilience-tests.md |
| NFT-RES-06 — Settings save with network drop — try/finally state reset | fast | resilience-tests.md |

### Excluded

- Settings happy path (covered by per-feature tests in Phase B).
- Settings RBAC redirect (covered in 12_test_protected_route_rbac).

## Acceptance Criteria

**AC-1: 500 recovery**
FT-N-13 / NFT-RES-05 — MSW returns 500 on settings PUT; assert: (a) `saving` flag is off (Save button no longer disabled / spinner not shown) within 2 s, (b) an error region is present in DOM.

**AC-2: Network drop**
FT-N-14 / NFT-RES-06 — MSW returns a network error; assert the same two conditions as AC-1.

**AC-3: Deadline**
NFT-PERF-09 — measure wall-clock from response receipt (or network failure) to DOM error visibility; assert ≤ 2 s.

## System Under Test Boundary

- System under test: `<SettingsPage>` + its save handler + `src/api/client.ts`.
- Allowed stubs: MSW for the settings PUT endpoint (returns 500 / network error per scenario).
- Disallowed: reading React state — test asserts DOM affordances (disabled button, error region).
- Expected observables per `results_report.md` rows 68-70 + the rows for NFT-RES-05/06.
