I am redesigning our job board website to be responsive.
Rather than just replace the existing site with the responsive site, I want to A/B test the new responsive site alongside the existing site so we compare various metrics side by side.
Half of all new visitors to the site will receive a cookie that triggers the responsive version of the site from then on. Existing visitors will remain on the old version of the site.
But I am concerned that Google will penalize us for showing different content seemingly randomly (the crawler will have a 50/50 chance of seeing the responsive version of the site). The content won't be massively different but there will be significant differences; new sections, things removed etc.
Because I'm using a cookie to change the rendered HTML, the URLs will be the same for either version. In fact the URLs need to be the same otherwise lots of reports and tracking will go awry.
Because the URLs of each A/B test are the same I can't use the
rel attribute to tell Google that the non-responsive version of this page is the canonical version.
Is there a correct way to handle this? Is it simply a bad idea to A/B test a site redesign?