Implements comprehensive test coverage for the ProductDetail component, verifying rendering, user interactions, and edge cases.

Changes

Testing Infrastructure

• Added vitest + @testing-library/react with jsdom environment
• Configured test setup and scripts (test, test:ui, test:run)

Test Suite (ProductDetail.test.tsx)

• Validates complete component tree rendering with product data
• Tests product information display (title, price, description, meta fields)
• Verifies fallback behavior for missing optional fields (brand → "N/A")
• Confirms navigation link and "Add to Cart" interaction
• Tests image rendering with thumbnail fallback

Code Organization

• Created src/contexts/index.ts barrel export to resolve missing useCartContext import
• Updated imports across Header, ProductCard, ProductActions, and main.tsx
• Fixed ESLint fast-refresh violation in CartContext.tsx

Example test helper demonstrating router + query setup:

const renderWithProviders = (productData: Product | null = mockProduct) => {
  const queryClient = new QueryClient({ /* ... */ });
  const productId = productData?.id ?? 1;
  
  if (productData) {
    queryClient.setQueryData(['product', productId], productData);
  }
  
  const router = createRouter({
    routeTree: rootRoute.addChildren([productRoute]),
    history: createMemoryHistory({ 
      initialEntries: [`/products/${productId}`] 
    }),
  });
  
  return render(
    <QueryClientProvider client={queryClient}>
      <RouterProvider router={router} />
    </QueryClientProvider>
  );
};

• Fixes Write unit tests for Product detail component #7

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.