```ts
// MyForm.stories.ts
import { expect, fireEvent, userEvent, within } from '@storybook/test';
import { Meta, StoryObj } from '@storybook/react';
// 👇 Must use this import path to have mocks typed correctly
import { getRouter } from '@storybook/nextjs/router.mock';

import MyForm from './my-form';

const meta: Meta<typeof MyForm> = {
  component: MyForm,
};

export default meta;

type Story = StoryObj<typeof MyForm>;

export const GoBack: Story = {
  async play({ canvasElement }) {
    const canvas = within(canvasElement);
    const backBtn = await canvas.findByText('Go back');

    await userEvent.click(backBtn);
    // 👇 Assert that your component called back()
    await expect(getRouter().back).toHaveBeenCalled();
  },
};
```