Software Engineering · Chapter 4 of 8
Code, review and the 9%
Testing appears in 9% of postings because it is assumed. Here is what is actually being assessed.
The low testing number is not licence to skip it — it means describing your testing discipline is not a differentiator. What is assessed is judgement: what deserves a test, what deserves a type, and what deserves neither.
What good judgement looks like
- Test behaviour, not implementation. A test that breaks when you refactor without changing behaviour is a liability, and a suite full of them is why teams stop refactoring.
- Test at the cheapest level that gives confidence. A pyramid is a heuristic, not a rule; some systems are genuinely better served by a thick integration layer.
- Prefer making states unrepresentable over testing that they do not occur. A type that cannot express an invalid combination removes a class of test entirely.
- Know what you are not testing and say so. ‘We have no coverage of the payment retry path and that is our biggest risk’ is a strong thing to be able to say.
Code review, which is 33% and is really about influence
Review is where engineering culture is actually set. The habits worth having: separate “this is wrong” from “I would have done it differently”, and say which you mean; ask a question rather than issue an instruction when you are not certain; approve with comments rather than blocking on preference; and review promptly, because review latency is usually the largest single component of lead time and it is entirely within your control.
On AI-assisted code, which 89% of postings now touch
The position that lands: specific about where you use it and where you do not. “I use it for tests, boilerplate and unfamiliar APIs, and I read anything touching auth, money or concurrency line by line” is a real answer.
The two failing answers are “I don't use it”, which reads as incuriosity in a market where 89% of postings mention it, and unqualified enthusiasm, which reads as someone who has not yet been burned by a confidently wrong suggestion in a subtle place.