There is supposedly a famous video series of Uncle Bob trying and failing to solve sudoku with TDD. He did not read any guides on solving it and tried from first principles instead, and bounced off of it.

It’s clear to me that if you don’t know what you’re building, testing it first has rubber duck value that can easily be overshadowed by Sunk Cost. I always test my pillars - the bits of the problem that are definite and which I will build off of.

Yes, starting with tests without market fit can also be fatal. But calling anything done without tests is just a slower poison. Before you airlift your brain to another unrelated problem you need to codify some of your assumptions. If you’re good at testing you can write them in a manner that makes it easy to delete them when requirements change. But that takes practice a lot of people don’t have because they avoid writing tests or they write the exact same kinds of tests for years at a time without every stretching their skills.

If you’re not writing tests you’re not writing good ones when you do. Testing is part of CI and the whole philosophy of CI is do the painful parts until you either grow callouses or get fed up and file off the scratchy bits. To avoid testing is to forget the face of your father.