In an integration test, using the test helper `triggerKeyEvent` on an input inside a ` ` does not submit the ` `

This question is based on the demo repo https://github.com/bartocc/so-enter-key-integration-test

This demo Ember.js app contains the <XFoo> component. When rendered, it displays a simple <form> with a text input and a submit button.

The <form> has an action bound on its submit event that will set the component's submitted property to true. By default, it is false.

The desired behaviour is to display a thank you message instead of the <form> after submitting it.

Here is the component's template:

  <span>
    Thank you for your submission
  </span>

  <form >
    
    <input type="text" />
    <button type="submit">
      Save
    </button>
  </form>

I've added 2 integration tests for <XFoo>:

• one tries to send the Enter keydown event to the <input> tag with the code

await render(hbs`<XFoo />`);
await triggerKeyEvent('input', 'keydown', 'Enter');

• the other clicks the submit button with

await render(hbs`<XFoo />`);
await click('button');

Both tests check the presence of the thank you message with:

assert.dom('span').hasText('Thank you for your submission', 'displays the thank you span');

The first test fails, the second one passes.

I would like to understand why using triggerKeyEvent does not submit the form.