How to test against "offline" or no network connection in browser mode?

[redjohnsh]

I'm building this http client that maps some fetch errors to more readable errors. For this, I need to test against lack of internet connection. I know that playwright has some "offline" mode and I want to use it with vitest. Any suggestion?

In the same way, I need to test against different network error such as cors, dns, etc.

[hi-ogawa]

I know that playwright has some "offline" mode and I want to use it with vitest.

You can access playwright's Page or BrowserContext API from custom commands https://vitest.dev/guide/browser/commands.html#custom-commands

Calling context.setOffline https://playwright.dev/docs/api/class-browsercontext#browser-context-set-offline is technically possible, but that might have an issue since it might also block how underlying Vitest runtime communicates with the server.