docs(18-01): complete file I/O routes tests plan

Tasks completed: 2/2
- Workflow route tests (14 tests)
- Save-generation route tests (15 tests)

SUMMARY: .planning/phases/18-api-route-tests/18-01-SUMMARY.md

.planning/ROADMAP.md

@@ -236,7 +236,7 @@ Plans:
 **Plans**: 5 plans
 
 Plans:
-- [ ] 18-01: File I/O routes (workflow, save-generation)
+- [x] 18-01: File I/O routes (workflow, save-generation)
 - [ ] 18-02: LLM route (Google, OpenAI providers)
 - [ ] 18-03: Generate route (Gemini provider)
 - [ ] 18-04: Generate route (Replicate, fal.ai providers)
@@ -319,7 +319,7 @@ Phases execute in numeric order: 1 → 2 → ... → 14 → 15 → 16 → 17 →
 | 15. Test Infrastructure | v1.2 | 1/1 | Complete | 2026-01-12 |
 | 16. Store Modularization | v1.2 | 1/1 | Complete | 2026-01-12 |
 | 17. Component Tests | v1.2 | 11/11 | Complete | 2026-01-13 |
-| 18. API Route Tests | v1.2 | 0/? | Not started | - |
+| 18. API Route Tests | v1.2 | 1/5 | In progress | - |
 | 19. Type Refactoring | v1.2 | 0/? | Not started | - |
 | 20. Integration Tests | v1.2 | 0/? | Not started | - |
 | 21. Fix Image Input & Deduplication | v1.2 | 0/? | Not started | - |

.planning/STATE.md

@@ -10,9 +10,9 @@ See: .planning/PROJECT.md (updated 2026-01-09)
 ## Current Position
 
 Phase: 18 of 22 (API Route Tests)
-Plan: 0 of 5 in current phase
-Status: Planning complete
-Last activity: 2026-01-13 - Created 5 plans for Phase 18
+Plan: 1 of 5 in current phase
+Status: In progress
+Last activity: 2026-01-13 - Completed 18-01-PLAN.md
 
 Progress: █████████░ 91%
 
@@ -128,6 +128,6 @@ Recent decisions affecting current work:
 ## Session Continuity
 
 Last session: 2026-01-13
-Stopped at: Planned Phase 18 (API Route Tests)
+Stopped at: Completed 18-01-PLAN.md (File I/O route tests)
 Resume file: None
-Next action: Execute Plan 18-01 (run /gsd:execute-plan .planning/phases/18-api-route-tests/18-01-PLAN.md)
+Next action: Execute Plan 18-02 (run /gsd:execute-plan .planning/phases/18-api-route-tests/18-02-PLAN.md)

.planning/phases/18-api-route-tests/18-01-SUMMARY.md

@@ -0,0 +1,114 @@
+---
+phase: 18-api-route-tests
+plan: 01
+subsystem: testing
+tags: [vitest, api-routes, fs-mocking, fetch-mocking, next.js]
+
+# Dependency graph
+requires:
+  - phase: 17-component-tests
+    provides: React Testing Library patterns and vitest configuration
+provides:
+  - API route testing patterns with fs/promises mocking
+  - NextRequest/NextResponse mocking patterns
+  - fetch mocking for HTTP URL handling
+  - Deduplication test patterns
+affects: [18-02, 18-03, 18-04, 18-05]
+
+# Tech tracking
+tech-stack:
+  added: []
+  patterns: [fs-mocking-with-factory-functions, nextrequest-mocking]
+
+key-files:
+  created:
+    - src/app/api/workflow/__tests__/route.test.ts
+    - src/app/api/save-generation/__tests__/route.test.ts
+  modified: []
+
+key-decisions:
+  - "Use factory function pattern for vi.mock with named exports (mockStat, mockMkdir, etc.)"
+  - "Mock NextRequest with json() and nextUrl.searchParams helpers"
+
+patterns-established:
+  - "fs mocking: Define mock functions at module scope, wire in vi.mock factory"
+  - "API route testing: Import POST/GET handlers directly, create mock request objects"
+
+issues-created: []
+
+# Metrics
+duration: 4 min
+completed: 2026-01-13
+---
+
+# Phase 18 Plan 01: File I/O Routes Summary
+
+**API route tests for workflow and save-generation with fs/promises mocking patterns established**
+
+## Performance
+
+- **Duration:** 4 min
+- **Started:** 2026-01-13T14:45:00Z
+- **Completed:** 2026-01-13T14:49:00Z
+- **Tasks:** 2
+- **Files modified:** 2
+
+## Accomplishments
+- Created 14 tests for workflow route (POST save, GET validation)
+- Created 15 tests for save-generation route (save, deduplication, MIME types)
+- Established fs/promises mocking pattern using factory functions
+- Established fetch mocking for HTTP URL handling
+
+## Task Commits
+
+Each task was committed atomically:
+
+1. **Task 1: Create workflow route tests** - `f7625ed` (test)
+2. **Task 2: Create save-generation route tests** - `17ee68c` (test)
+
+**Plan metadata:** (this commit)
+
+## Files Created/Modified
+- `src/app/api/workflow/__tests__/route.test.ts` - 14 tests covering POST save and GET validation
+- `src/app/api/save-generation/__tests__/route.test.ts` - 15 tests covering save, deduplication, validation
+
+## Decisions Made
+- Used factory function pattern for vi.mock to define mock functions at module scope
+- Mock NextRequest with json() and nextUrl.searchParams helpers rather than full request objects
+
+## Deviations from Plan
+
+### Auto-fixed Issues
+
+**1. [Rule 3 - Blocking] Fixed mocking pattern for vitest**
+- **Found during:** Task 1 (workflow route tests)
+- **Issue:** vi.mocked(fs.stat).mockResolvedValue() failed - vitest auto-mocking doesn't expose mock functions directly
+- **Fix:** Defined mock functions at module scope (const mockStat = vi.fn()) and wired them in vi.mock factory
+- **Files modified:** src/app/api/workflow/__tests__/route.test.ts
+- **Verification:** Tests pass with new mocking pattern
+- **Committed in:** f7625ed
+
+**2. [Rule 3 - Blocking] Fixed missing matcher**
+- **Found during:** Task 2 (save-generation route tests)
+- **Issue:** toEndWith() matcher not available in vitest/chai
+- **Fix:** Used expect(data.filename.endsWith(".png")).toBe(true) instead
+- **Files modified:** src/app/api/save-generation/__tests__/route.test.ts
+- **Verification:** Tests pass with boolean assertion
+- **Committed in:** 17ee68c
+
+---
+
+**Total deviations:** 2 auto-fixed (2 blocking), 0 deferred
+**Impact on plan:** Both auto-fixes were necessary for tests to function. No scope creep.
+
+## Issues Encountered
+None - plan executed successfully with blocking issues resolved inline.
+
+## Next Phase Readiness
+- fs mocking pattern established for use in subsequent API route test plans
+- fetch mocking pattern established for HTTP URL handling
+- Ready for 18-02 (LLM route tests)
+
+---
+*Phase: 18-api-route-tests*
+*Completed: 2026-01-13*