As you said, this is in a very different context. He was building an OS, which was sold to highly technical users running their own programs on it. I'm talking

As you said, this is in a very different context. He was building an OS, which was sold to highly technical users running their own programs on it. I'm talking about "shrinkwrap" software like Word or something. There's nothing even close to testing for that this is not just "system testing" it.