No, testing does not cause any issues regarding cloaking. Google uses similar techniques in their website optimizer and understands what being done with testing.

Cloaking involves showing a page to the search engine spider that is never seen by a visitor to the page. Since a percentage of visitors to your test page are seeing the control page that search engine spiders see, this is not cloaking.

However, due to this, we do recommend that you code the final winning test page as page the spiders see. Our software allows you to show the winning page to visitors and use it as your new control page without actually coding it on your site. This is okay for the short term as you continue testing, but once finished, code the final page on your site.