Redaria, opticians do indeed perform eye tests in China at all of the major dispensers of optical products here.  Most of the time the "examination" if you were to call it that is included in the purchase price of the glasses that one is most likely purchasing.  If you have serious concerns, then there are always the ophthalmologists to be found in the larger hospitals in the city where you live.  An optician's visit at best is cursory and often not at all as accurate as would have been a consultation with an opthalmologist.

I'm thinking by 'eye test' you mean prescription? As 'numbers' mentioned already - almost any mid-larger store selling glasses will do it for you. I do believe mine was also included in the price of the price.

Trying to recall..  I want to say it about $45 all total (prescription test, frames, lenses) but it seems to me that also included non-prescription sunglasses. 

If you are in Beijing, go to Wanfujing, there is a VERY BIG and very well known place. The cost for an examination is about 10kuai..... but if you want buy the glasses from them, be prepared to spend a couple of thousands. I suggest you go to a hospital and let a proper doctor examine you.

Yes they do and believe it or not it won't cost you an arm and a leg!