feat(ST-1112): wire story-promotion into saveTask and PATCH /api/tasks/:id

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

__tests__/actions/tasks-dialog.test.ts

@@ -18,10 +18,14 @@ vi.mock('@/lib/prisma', () => ({
       create: vi.fn(),
       update: vi.fn(),
       delete: vi.fn(),
+      findMany: vi.fn(),
     },
     story: {
       findFirst: vi.fn(),
+      findUniqueOrThrow: vi.fn(),
+      update: vi.fn(),
     },
+    $transaction: vi.fn(),
   },
 }))
 
@@ -35,8 +39,14 @@ const mockPrisma = prisma as unknown as {
     create: ReturnType<typeof vi.fn>
     update: ReturnType<typeof vi.fn>
     delete: ReturnType<typeof vi.fn>
+    findMany: ReturnType<typeof vi.fn>
   }
-  story: { findFirst: ReturnType<typeof vi.fn> }
+  story: {
+    findFirst: ReturnType<typeof vi.fn>
+    findUniqueOrThrow: ReturnType<typeof vi.fn>
+    update: ReturnType<typeof vi.fn>
+  }
+  $transaction: ReturnType<typeof vi.fn>
 }
 const mockSession = getIronSession as ReturnType<typeof vi.fn>
 
@@ -58,6 +68,10 @@ const STORY = { sprint_id: 'sprint-1' }
 beforeEach(() => {
   vi.clearAllMocks()
   mockSession.mockResolvedValue({ userId: 'user-1', isDemo: false })
+  // Pass-through transaction so saveTask's $transaction wrapper executes its callback inline.
+  mockPrisma.$transaction.mockImplementation(async (run: (tx: typeof prisma) => Promise<unknown>) => {
+    return run(prisma)
+  })
 })
 
 // ─── saveTask ────────────────────────────────────────────────────────────────
@@ -114,6 +128,47 @@ describe('saveTask — edit (cross-tenant scope)', () => {
   })
 })
 
+describe('saveTask — edit met status-promotie', () => {
+  it('promotes story naar DONE wanneer status flip naar DONE alle siblings DONE maakt', async () => {
+    mockPrisma.task.findFirst.mockResolvedValue({ id: 'task-1', status: 'IN_PROGRESS' })
+    mockPrisma.task.update.mockResolvedValue({
+      id: 'task-1',
+      title: 'Test taak',
+      status: 'IN_PROGRESS',
+      story_id: 'story-1',
+      implementation_plan: null,
+    })
+    // Wanneer de helper draait, gebruikt-ie tx.task.update voor de status-flip.
+    // Dezelfde mock vangt beide updates op; tweede return-value voor de status-update.
+    mockPrisma.task.update.mockResolvedValueOnce({
+      id: 'task-1',
+      title: 'Test taak',
+      status: 'IN_PROGRESS',
+      story_id: 'story-1',
+      implementation_plan: null,
+    }).mockResolvedValueOnce({
+      id: 'task-1',
+      title: 'Test taak',
+      status: 'DONE',
+      story_id: 'story-1',
+      implementation_plan: null,
+    })
+    mockPrisma.task.findMany.mockResolvedValue([{ status: 'DONE' }, { status: 'DONE' }])
+    mockPrisma.story.findUniqueOrThrow.mockResolvedValue({ status: 'IN_SPRINT' })
+
+    const result = await saveTask(
+      { ...VALID_INPUT, status: 'DONE' },
+      { taskId: 'task-1', productId: 'p-1' },
+    )
+
+    expect(result).toMatchObject({ ok: true })
+    expect(mockPrisma.story.update).toHaveBeenCalledWith({
+      where: { id: 'story-1' },
+      data: { status: 'DONE' },
+    })
+  })
+})
+
 describe('saveTask — create (cross-tenant scope)', () => {
   it('retourneert forbidden als story buiten scope valt', async () => {
     mockPrisma.story.findFirst.mockResolvedValue(null)