Ember.js test page keeps refreshing automatically

I'm trying to follow an example integration test from here: https://guides.emberjs.com/release/testing/testing-components/ (Testing Actions)

My problem is that the Test output keeps refreshing automatically, perpetually, for some reason?

Test code:

test('Can handle submit action', async function (assert) {
    /*
    * THIS TEST HAS PROBLEMS
    * THE PAGE CONSTANTLY REFRESHES FOR THIS TEST, NO IDEA WHY, NEED TO INVESTIGATE
    */
    assert.expect(1);

    // test double for the external action
    this.set('externalAction', (actual) => {
      const expected = {inputValue: 'test'};
      assert.deepEqual(actual, expected, 'submitted value is passed to external action');
    });

    await render(hbs``);

    // click the button to submit the form
    await click('#submitButton');
  });

Component.js:

import Component from '@ember/component';
import {computed} from '@ember/object';

export default Component.extend({
  inputValue: '',
  submitText: 'Save',
  inputIsValid: computed('inputValue', function () {
    return this.inputValue.length > 3;
  }),

  actions: {
    save(inputValue) {
      if (this.inputIsValid) {
        this.saveAction(inputValue); // pass action handling to route that uses component
      }
    }
  }
});

component template:

<br>
<br>
<form onsubmit=>
    
      <div style="color: red" class='validationMessage'>
        Hey it is not valid!
      </div>
    

    <label id="inputLabel"></label>
    
    <br>
    <button type="submit" id="submitButton" class="btn btn-primary"></button>
</form>

I thought it might be because the form in the template keeps submitting, but that can't be the case since it should only click submit once. Any help much appreciated!