TextField tests - onChange() trigger

TextField.test.tsx

import {trigger} from '@shopify/enzyme-utilities';

...

describe('onChange()', () => {
  it('triggers when the user types', () => {
    const onChangeSpy = jest.fn();
    const event = {};
    const textField = mount(
      <TextField {...mockProps} onChange={onChangeSpy} />,
    );
    trigger(textField.find('input'), 'onChange', event);
    expect(onChangeSpy).toHaveBeenCalledTimes(1);
  });
});