[Feature] Emulate reduced motion media query

[LarsDenBakker]

Puppeteer allows emulating the reduced motion media query: https://github.com/puppeteer/puppeteer/blob/v5.2.1/docs/api.md#pageemulatemediafeaturesfeatures

It would be great if we can support this in playwright as well. It's widely supported in browsers: https://caniuse.com/#feat=prefers-reduced-motion

[pavelfeldman]

Could you help us prioritizing this? Does it come from a customer or is it a feature parity request?

[LarsDenBakker]

It's about feature parity. It's same story as #3321 - we offer bindings for emulating media features from tests, using both puppeteer and playwright. Right now we throw an error when trying to emulate reduced motion when running tests with playwright.

[RyKilleen]

This would be incredibly useful for testing purposes. For accessibility purposes, we disable all animations based the prefers-reduced-motion media query.

Being able to set it to avoid fragile tests would save a bunch of time overall!

[evanleck]

FWIW I'd like to be able to emulate this media query so I don't have to wait for animations to end in my tests. Of course something like #4055 would help as well but without either I'm just doing arbitrary page.waitForTimeouts all over the place haha