폼 제출 시 FormData 테스트

test('폼 제출 시 formData 확인', () => {
  const handleSubmit = jest.fn((e: React.FormEvent<HTMLFormElement>) => {
    e.preventDefault()
    const formData = new FormData(e.target as HTMLFormElement)
    const data = Object.fromEntries(formData.entries())
    expect(data).toEqual({ username: 'testuser', password: 'password' })
  })

  render(<LoginForm onSubmit={handleSubmit} />)

  fireEvent.change(screen.getByPlaceholderText('아이디'), {
    target: { value: 'testuser' },
  })
  fireEvent.change(screen.getByPlaceholderText('비밀번호'), {
    target: { value: 'password' },
  })
  fireEvent.click(screen.getByRole('button', { name: '로그인' }))

  expect(handleSubmit).toHaveBeenCalled()
})

const formData = new FormData();
const single = document.querySelector('input[type="file"]');
const multiple = document.querySelector('input[type="file"][multiple]');

formData.append('single', single.files[0]);

[...multiple].forEach((file, index) => {
  formData.append(`multiple_${index}`, file);
})

fetch('https://example.com/posts', {
  method: 'POST',
  body: formData,
})