[hansvm]

It's comparable in the way described in sentence #2:

> An individual company having specific needs isn't at odds with a general statement being broadly true.

Google needs certain things more than reduced carbon emissions, and Jane Street needs certain things more than whatever else they could spend that dev time on.

[thehappyfellow]

Fine but cutting the thought process at "it depends" is not a great way to understand what's happening here. You can explain anything happening at any company by saying "they need certain things more than whatever else they could spend that time on".

Why is PBT useful at Jane Street, at least more than in other places? Is it the use of functional language? Average Jane Street dev being more familiar with PBT? Is the domain particularly suited to this style of testing?

Explicitly, my claim is that the biggest bottleneck is education on how to use PBT effectively and Jane Street is not using them to get an extra mile in safety, they use it because it's the easiest way to write large chunk of the tests.

[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.