If you are testing your new website layout, you might be reloading your website pages again-n-again. And if these pages contain Google Ads, each time your reload your page, you make a request to Google Ads Server for a new set of ads.
Certainly Google is unaware that you are testing your website and it might even penalize your account for "click-fraud" since the IP requesting ads remains same. And if in the worst-case scenario, you might accidently click on your own ads. And these extra "ad impressions" will also chance your CTR data.
One simple way to avoid this serious problem is to remove the Adsense code altogether from your page before testing. But this may not be the best solution as your Google Ads are an important part of your layout. So here are a few simple but effective workarounds:
1. Instead of using Adsense code, add a static graphic (jpg image) with the same dimesions as your adsense code. (Google itself provides static images of various ad formats.)
2. Modify the value of google_ad_client to something like "pub-googleIamTesting"
3. Add another line to Google Adsense code google_adtest = "on"; Don't forget the semicolon.
4. Though there is no official comment, it is safer to remove the google_ad_channel variable.
Or contact Google Adsense Team with your query. Google folks are very quick to respond.
Google AdSense policies require that websites displaying Google ads be active and not under construction. When your site is complete and active, you may add the AdSense