Add support for request interception

[Wigny]

Using phoenix_test_playwright, I noticed there is no documented way of mocking requests by the client to external files, like when loading an external image in a page.

This seems to be possible to achieve in the JS library by using the page.fulfill helper.

Therefore, I wonder if we could have similar helpers in this library that would allow us to call some sort of callback to intercept requests, returning our custom responses.

[ftes]

It looks like this requires some logic in the (our elixir) client.
https://github.com/microsoft/playwright/blob/21bb265aa1f290b297cc7c9c78596a785216b667/packages/playwright-core/src/client/page.ts#L521-L524

Which makes sense, because Playwright.js/python/... doesn't just allow you to serve static files, but also implement dynamic route handlers in your client language.

That being said: Definitely possible. Just not a small change.
Would you be willing to look into this? Happy to provide assistance if you'd like.

[ftes]

Are you in control of the server?

If you want to mock an external request, can you instead point external requests to your (phoenix?) server? E.g. via test config. Then you could merrily mock away with the default tools available on your server.

For the usual phoenix_test_playwright use cases, that would be the way to go.
No idea if that fits your use case.