Trying to understand where you're coming from here... I should write tests for every portion of the .NET Framework my app uses because it might break on a security update?

If Microsoft had a history of breaking things with .NET framework security patches, then yes, absolutely. That's what people are saying happens with Rails, isn't it?

What are you, crazy? No, what you do is that you jump ship.

I think he's probably talking about dealing with the fallout from failed tests rather than the tests themselves.