If Chrome and Safari are both based on WebKit, does that mean I don't have to test both browsers?

Question

If Chrome and Safari are both based on WebKit, does that mean I don't have to test both browsers?

... or are there certain situations where I should explicitly test both Chrome and Safari?

Answer 1

You should test both browsers to be sure. You'll be ok 99% of the time but you want to make sure.

Answer 2

Everything else beside the basic HTML rendering engine is still different. If only basic HTML/CSS compatibility is important, I guess it's fine to test one browser.

However, the JavaScript engines of Chrome and Safari are completely different, vector graphics are rendered by different engines, HTML5/video tag stuff is implemented completely different, etc. The list goes on.

Overall I'd recommend to test with both browsers.