Stub web project

web/src/components/App.test.jsx

@@ -0,0 +1,15 @@
+import { render, screen, fireEvent } from '@testing-library/react'
+import App from './App'
+
+describe('App', () => {
+  it('renders without crashing', () => {
+    render(<App />)
+    expect(screen.getByText(/React App/i)).toBeInTheDocument()
+  })
+
+  it('calculates correctly when button is clicked', () => {
+    render(<App />)
+    fireEvent.click(screen.getByText(/Calculate/i))
+    expect(screen.getByText(/Result: 8/i)).toBeInTheDocument()
+  })
+})