[hitchstory]

>Why is PBT useful at Jane Street, at least more than in other places?

Because trading firms write a lot more algorithmic code than most businesses. Trading strategy code is intensely algorithmic and calculation heavy by its very nature as is a lot of the support code written around it.

At least, that's what it was like when I worked in a trading firm. Relatedly, it was one of the few projects Id worked on where having 95% unit tests and 5% integration tests made perfect sense. It fitted the nature of the code, which wasnt typical of most businesses.

Somebody else wrote that they wrote a lot of numerical code in another business for which property testing is extremely useful and again, I dont doubt that either. 95% is still != 100% though.