Almost every engineering team agrees, in principle, that they should have good automated tests. Then almost every team finds a reason not to write them. The reason is nearly always the same. Tests take time, the feature is due, and testing is the thing that gets cut. AI-assisted coding just took that excuse away, at the exact moment you need tests more than ever.
A quick refresher on the pyramid
The testing pyramid is a simple idea about where to invest your testing effort. At the wide base sit unit tests: many small, fast tests that check individual pieces in isolation. In the middle, a smaller number of integration tests confirm that those pieces work together. At the narrow top, a handful of end-to-end tests exercise the whole system the way a user would. The shape matters. You want lots of fast, cheap tests at the bottom and only a few slow, expensive ones at the top. Get it upside down, all end-to-end and no units, and your suite becomes slow and flaky until nobody trusts it.
The excuse, and why it was always expensive
The classic objection to testing was time. Writing thorough tests can take as long as writing the code they cover, and under deadline pressure that feels like a luxury. So teams shipped untested code, promised themselves they would add tests later, and later never came. The cost arrived anyway, as regressions, as fear of touching working code, as slow and risky releases. Untested code is not faster. It just pushes the cost downstream and hides it where it is harder to see.
AI removed the excuse
Writing tests is exactly the kind of work AI-assisted coding is good at. Describe the behavior, and an agent can generate the unit and integration tests to cover it, including the tedious edge cases a tired engineer would skip at the end of a long day. The thing that used to demand real time and discipline is now fast and cheap. The last good excuse for skipping automated testing is gone.
And now you need the tests more than ever
There is a deeper reason this matters right now. When AI agents are writing a large share of your code, your automated tests are not a quality nicety. They are the guardrail that makes that volume safe. As I wrote about the 3,000-line day, when a human cannot read every line, your test suite and your CI gates are what review the work. A strong, well-shaped testing pyramid is the thing standing between fast AI output and a production incident. The teams still treating tests as optional are the ones who will get hurt as their code volume climbs.
What good looks like now
Aim for the shape: a broad base of fast unit tests, a solid layer of integration tests on the paths that matter, and a focused set of end-to-end tests on your most important user journeys. Wire all of it into continuous integration so nothing merges without passing. Use AI to write and maintain the tests so the cost stays low. There has never been a cheaper time to do testing well, and never a more important one.
Building this testing discipline in, especially as teams adopt agentic workflows, is part of what I do as a fractional CTO with Artificer Innovations. If your team has been meaning to get serious about testing, now is the moment, and let’s talk.