The purpose of testing

Oh his blog, Andy Pohls tells an interesting story of a customer who refused to deploy code that did not have an automated test. Moreover, the output of the missing test in question was an XML file. When the customer was shown how to read the XML that was being passed between systems, he realized that it did not suit the business needs.
But what I found most thought-provoking was one of the comments to the post, written by Michael Bolton:

It’s unusual to hear that the customer learned something and used the information obtained from creating the test. . . This is much closer to my view of what is really important about testing: discovering and revealing information so that people can make informed decisions. Most of the time, we hear about something different: confirming and validating information so that people can feel reassured knowing that last week’s tests are still passing this week. That might be reassuring, but it has enormous potential for self-deception. We need always to ask if our tests are helping us to learn, not just helping us to sleep.

I’ll have to think about how sharing tests with customers can enhance quality.