With any question like this, we tend to see 2 groups of replies. One group says if you even suspect a safety issue, replace it without question. The other group says wait a minute, that thing is still plenty strong and there's no way you're going to break in normal riding. No disrespect whatsoever to the first group, but I'm in the second. Certainly you can test it by applying some extreme force by doing something like what gyozadude suggests. Of course I'd watch for any deformation or cracking over time, but it doesn't seem remotely likely to me.