feat: add ErrorPage component with back-to-home link

src/components/ErrorPage.test.tsx

@@ -0,0 +1,27 @@
+import { render, screen } from '@testing-library/react'
+import { describe, expect, it } from 'vitest'
+import ErrorPage from './ErrorPage'
+
+describe('ErrorPage', () => {
+  it('renders default 404 content', () => {
+    render(<ErrorPage />)
+
+    expect(screen.getByText('404')).toBeInTheDocument()
+    expect(screen.getByRole('heading', { name: 'Page introuvable' })).toBeInTheDocument()
+  })
+
+  it('renders a link back to the home page', () => {
+    render(<ErrorPage />)
+
+    const link = screen.getByRole('link', { name: "Retour à l'accueil" })
+    expect(link).toHaveAttribute('href', '/')
+  })
+
+  it('uses custom code, title and message when provided', () => {
+    render(<ErrorPage code={500} title="Erreur serveur" message="Une erreur est survenue." />)
+
+    expect(screen.getByText('500')).toBeInTheDocument()
+    expect(screen.getByRole('heading', { name: 'Erreur serveur' })).toBeInTheDocument()
+    expect(screen.getByText('Une erreur est survenue.')).toBeInTheDocument()
+  })
+})