[tjr]

I have mostly worked in aerospace software, and find this rather horrifying. I suppose, if your tests are in fact good and comprehensive enough, there could be a logical argument for not needing to understand the code, but if we're talking people's safety in the hands of your software, I don't know if there is any number of tests I would accept in exchange for willingly giving up understanding of the code.

[asadotzler]

You're transferring the need to be really good at coding and understanding code to the need to be really good at testing and understanding tests, which 9/10 times requires being good at coding and understanding code. There are no free lunches.