Getting from tested to battle-tested

Testing is an essential part of building reliable software. It’s a form of documentation,
a reminder of mistakes of the past, and a boost of confidence when you want to
refactor. But mostly, testing is a way of showing that your code is correct and
resilient. Because it’s so important, we’ve invested a lot of effort at Jane Street to
develop techniques that make tests clearer, more effective, and more pleasant to write.