Aetna CEO Mark Bertolini appeared on CNBC's "Squawk Box" on Monday to deliver a brutal review of the Affordable Care Act's launch.

"When you implement a project of this size, the first thing is unit testing, then application testing, and then integrated testing, and then scaleability testing and user testing," Bertolini said. "That plan is usually a lot longer than some of the application development itself. That's happening on the fly."

The hosts were disbelieving. "None of that was done beforehand?" one asked.

"All of it has been on the fly," Bertolini said.

My understanding is there was some testing done beforehand. So "all" might be an exaggeration. But that testing didn't go well. And there clearly wasn't nearly enough of it.

There are only a few groups who have real insight into what's happening in the guts of the federal insurance portal right now. The Obama administration itself, or course. But they haven't been releasing very much information, and they have an obvious incentive to put a positive spin on the situation.

The insurance industry, however, also has an unvarnished view into the back end because the system ultimately is tied in to their computers. And, at this point, the insurance industry badly wants the administration to succeed: If the federal health-care marketplaces fail to sign up enough people, or fail to sign up a good mix of people, it will be a disaster for the insurers participating, too. So Aetna's CEO is well worth listening to.

In the interview -- which you can read more excerpts from here -- Bertolini predicts that the Obama administration will end up extending the open enrollment period until at least March 31. He also says it could take up to three years until the exchange's problems are fully sorted out.