Nope! They solved it the opposite way. Their bug tracking system consisted of individual customers who called up to report bugs. I.e. Joe Blow would call up and say "Hey, I'm supposed to see 231 shares, but I only see 219 shares."

That would result in a bug report. The bug report was that Joe Blow saw that outcome. In other words, the bug report didn't contain anything about the code itself.

They had an entire division of support people whose job was to track these bugs, and to fix them.

In order to fix the bug, they would manually edit the database, or do whatever was necessary to make sure Joe Blow saw the right value again. But they never changed the code; they weren't programmers.

Once Joe Blow was happy, they closed the bug report as "fixed."

Therefore, no tests were ever required.

It was ... impressive? I think? I couldn't mentally process what I was seeing at the time. But "impressive" is probably the right word. After all, the system worked.