vitest with playwright mock error

[ezenkico]

I'm using playwright with vitest to test my sveltekit application. I'm attempting to test a post request that is sent from one of the api endpoints via axios

I have attempted the following all with the same error.

const spy = vi.spyOn(axios, "post");

vi.mock("axios");

vi.mocked(axios, true).post.mockResolvedValue({
  data: {}
});

The error I keep getting is

TypeError: Cannot redefine property: Symbol($$jest-matchers-object)
Has anyone ever seen this before?

[ayazemregm]

I get the same error when I try to use component testing.

TypeError: Cannot redefine property: Symbol($$jest-matchers-object)

I just set it up and run the test that is in the guideline

[paumur]

I had the same issue. My problem was that in the playwright-ct.config.ts file there is testDir property. You have to change the path where your tests are located.

[ValentinoFilipetto]

Yes I had the same problem! I indeed suggest to have a look at playwright.config.ts

[dario-piotrowicz]

I've encountered the issue, I've tried hacking around and patching the playwright node_modules files so to avoid this jest matchers object conflict.

However after doing that I encounter a new error anyways:

So I don't think vitest utilities can just be reused outside of vitest itself.

[dario-piotrowicz]

As per this comment, to use mocks outside of vitest itself they should simply be imported from @vitest/spy 🙂

it does work for me 🥳

[kmturley]

I have the same issue in a project with both:

• vitest unit tests
• playwright end-to-end tests

Inside the ./tests directory I have:

• api.spec.ts
• index.test.ts

playwright.config.ts

import { defineConfig } from '@playwright/test';
export default defineConfig({
  testDir: './tests'
});

npx playwright test --debug
TypeError: Cannot redefine property: Symbol($$jest-matchers-object)
    at /my-site/node_modules/@vitest/expect/dist/index.js:589:10

The issue appears to be that playwright is running both files:

• api.spec.ts
• index.test.ts

If I comment out the vitest unit tests it runs fine.
A better fix was to update playwright.config.ts to only match *.spec.ts files:

import { defineConfig } from '@playwright/test';

export default defineConfig({
  testDir: './tests',
  testMatch: '*.spec.ts'
});

and vitest.config.ts also needed updating:

/// <reference types="vitest/config" />
import { defineConfig } from 'vite';
export default defineConfig({
  test: {
    include: ['./tests/**/*.test.ts']
  },
});