POST/PUT/DELETE visits with Inertia forms or links become GET requests in Capybara E2E tests

[EmCousin]

Hi there,

First of all, thanks for all the great work on Inertia and its Rails integration.

When writing E2E tests with Rspec and Capybara, I noticed that submitting an Inertia powered form or clicking on an Inertia powered link always sends a get request to the server, ignoring the verb.

Example with a form:

Take the following client-side rendered component:

import React from 'react'
import { useForm } from '@inertiajs/inertia-react'

const MyForm = () => {
  const { post, data, setData, processing, errors } = useForm({
    name: '',
    email: '',
  });

  const handleSubmit = (e) => {
    e.preventDefault();
    post('/my/endpoint');
  };

  return (
    <form onSubmit={handleSubmit}>
      <input type="text" name="name" value={data.name} onChange={e => setData('name', e.target.value)} />
      <button type="submit">Submit</button>
    </form>
  )
}

• ✅ When submitting the form, a POST request is sent to the server.
• 🔴 But when submitting the form in a Capybara test, it sends a GET request

Example with a link:

Take the following component:

import React from 'react'
import { Link } from '@inertiajs/inertia-react'

const MyLink = () => <Link href="/my/endpoint" method="post">My Link</Link>

export default MyLink;

• ✅ When clicking on the link, a POST request is sent to the server.
• 🔴 But when clicking on the link in a Capybara test, it sends a GET request

I've been able to reproduce this issue in a Rails 7.1.3 app with Inertia 2.2.8