What tool can I use to test the :contains() CSS3 pseudo-class in a browser?

Question

I am trying to develop CSS selectors to use with Selenium. In particular I want to use the pseudo-class :contains(). Although the W3 has a draft of CSS3 with :contains() i

Answer 1

I'm not seeing the :contains() selector anywhere and have never encountered it myself.

No pseudo-class comes up: http://caniuse.com/#search=contain