diff --git a/__tests__/components/jobs/job-detail-pane.test.tsx b/__tests__/components/jobs/job-detail-pane.test.tsx
new file mode 100644
index 0000000..9e51f87
--- /dev/null
+++ b/__tests__/components/jobs/job-detail-pane.test.tsx
@@ -0,0 +1,75 @@
+// @vitest-environment jsdom
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { render, screen, fireEvent } from '@testing-library/react'
+import '@testing-library/jest-dom'
+import type { JobWithRelations } from '@/actions/jobs-page'
+
+vi.mock('@/actions/claude-jobs', () => ({
+  restartClaudeJobAction: vi.fn(),
+}))
+
+vi.mock('sonner', () => ({ toast: { error: vi.fn() } }))
+
+import { restartClaudeJobAction } from '@/actions/claude-jobs'
+import JobDetailPane from '@/components/jobs/job-detail-pane'
+
+const mockAction = restartClaudeJobAction as ReturnType<typeof vi.fn>
+
+function makeJob(status: JobWithRelations['status']): JobWithRelations {
+  return {
+    id: 'job-1',
+    kind: 'TASK_IMPLEMENTATION',
+    status,
+    taskCode: 'T-1',
+    taskTitle: 'Test taak',
+    ideaCode: null,
+    ideaTitle: null,
+    sprintGoal: null,
+    sprintCode: null,
+    productName: 'Scrum4Me',
+    modelId: null,
+    inputTokens: null,
+    outputTokens: null,
+    cacheReadTokens: null,
+    cacheWriteTokens: null,
+    costUsd: null,
+    branch: null,
+    prUrl: null,
+    error: null,
+    summary: null,
+    description: null,
+    verifyResult: null,
+    startedAt: null,
+    finishedAt: null,
+    createdAt: new Date('2026-01-01'),
+    sprintRunId: null,
+  }
+}
+
+beforeEach(() => {
+  vi.clearAllMocks()
+  mockAction.mockResolvedValue({ success: true })
+})
+
+describe('JobDetailPane restart button', () => {
+  it('toont de knop voor FAILED-jobs', () => {
+    render(<JobDetailPane job={makeJob('FAILED')} isDemo={false} />)
+    expect(screen.getByRole('button', { name: /opnieuw starten/i })).toBeInTheDocument()
+  })
+
+  it('toont de knop niet voor DONE-jobs', () => {
+    render(<JobDetailPane job={makeJob('DONE')} isDemo={false} />)
+    expect(screen.queryByRole('button', { name: /opnieuw starten/i })).not.toBeInTheDocument()
+  })
+
+  it('roept restartClaudeJobAction aan met het juiste id bij klik', () => {
+    render(<JobDetailPane job={makeJob('FAILED')} isDemo={false} />)
+    fireEvent.click(screen.getByRole('button', { name: /opnieuw starten/i }))
+    expect(mockAction).toHaveBeenCalledWith('job-1')
+  })
+
+  it('knop is disabled in demo-modus', () => {
+    render(<JobDetailPane job={makeJob('FAILED')} isDemo={true} />)
+    expect(screen.getByRole('button', { name: /opnieuw starten/i })).toBeDisabled()
+  })
+})