Hi! We definitely encourage lots of testing before you send out an email campaign, and I can understand where those test results might feel like they are bogging down your response section.
While there's not a way to prevent test mailings from showing up in the response section, there is a way where you can quickly delete multiple mailings from your response page. Here's a quick video to show you how: http://screencast.com/t/tlOn25AI0
Hopefully that will help you to quickly remove those test mailings from your response section. I can see the benefit of being able to turn response data for tests in situations like this, so I think that's a great idea as a feature request!
Hello! I’ve been talking with our product owners about what our plans are here. We don't have any planned work around this, but we're considering multiple options that would make managing test mailings (and all mailing types) much easier down the road. I appreciate your feedback and encourage others who would like a different way to manage mailings in Response to either click Me Too or comment below!