Google announced quietly on Google+ that they have an opt in beta where AdWords advertisers can create draft campaigns and set them to run, with part of your campaign budgets, to test to see how well those drafts do in the real world.
Google calls this "Campaign drafts and experiments." Campaign drafts and experiments is a beta feature that lets you quickly test changes to your AdWords campaigns, measure results, and apply those changes to help you meet your business goals, Google said. Here is the example Google has given:
Let’s say you want to increase your campaign mobile bid adjustment, but would first like to test how that change performs on a portion of your campaign traffic. Using campaign drafts and experiments, you can create a draft based on your existing campaign settings, set the new bid adjustment, then convert your draft into an experiment to test how those changes perform against your original campaign. Your original campaign will share budget with your experiment campaign, so you can decide how much traffic to split between the two.
To request into this beta, fill out this form.
Forum discussion at Google+.