How do I test filter changes?

Rating: +0

You should see the filter changes the next time that GA process your
data. I believe that happens every 3 to 6 hours.

To test profile filters I suggest you set up a 'test' profile based on
your 'production' profile. You can then apply your filters to this
profile and validate the results. Read here for more information about test profiles.

If you need RegEx help, there are a number of tools on the web. My favorite is the RegEx coach. You can find a link to it here.