[diehunde]

It's very nerve-racking for people who like to have a deep understanding of everything they ship. A modernization project that would take you 2 months now can be done in a week or less because you don't need to go deep into the business logic to replicate it and instead you can just focus on designing the boundaries and interfaces properly. Then like the article mentions, just create a good test harness to test parity as much as you can. I was feeling very conflicted about this myself, but then I thought: I have these other systems I have to maintain on a daily basis and I also don't understand the internals and business logic that well because I wrote them years ago and haven't changed much. I just rely on the test suite if something needs to be changed or the code structure if I need to see how something in particular works.

[lucketone]

To have good test harness you need to get deep into business logic. Am I missing something?

[mandeepj]

> It's very nerve-racking for people who like to have a deep understanding of everything they ship.

A deep domain knowledge of your industry and your business (company/org) makes you very valuable in your team and your company. I've seen people survive layoffs and other cost-cutting cycles just because they possessed immense knowledge compared to those who did not.

[triage8004]

You clearly know what you are talking about but I didn't understand about your testing methods explanation at all.