next.js/test/production/jest/rsc/app/component.jsx

import { useState } from 'react'
export default function Counter() {
  const [count, setCount] = useState(0)
  return (
    <>
      <h2>{count}</h2>
      <button type="button" onClick={() => setCount(count + 1)}>
        +
      </button>
    </>
  )
}