[always_good]

Only if you are referring to perfect tests which cost zero time to write/maintain and only the tests written that eventually will catch an issue.

Otherwise, tests have a cost just like any other code. You can see this by looking at both extremes: perfect tests (described above) and useless tests. For example, tests that make your codebase too brittle, tests that don't actually test anything useful, spending too much time writing tests, spending a lot of time writing tests for precisely the code with high disposability, tests that are too coupled with the code, stupid tests that should be removed but won't be because tests tend to be append-only, etc.

Testing is an advanced topic where every +1 unit you spend on testing doesn't mean your application is now +1 unit more robust. +1 unit of time spent in tests can even mean your application is -2 units worse because testing is a trade-off.

So tests are more than capable of hamstringing your unlaunched MVP. They're also capable of being the reason you launched your MVP sooner than later. But the costs of testing are no illusion.

[nradov]

Tests save you time. They have a negative cost.

[leoedin]

Some tests save you time. Some tests don't. It's perfectly possible to write a huge, fragile, heavily coupled test suite which takes days or weeks to modify when you make even a tiny change to the code it's testing.

Just as code falls on a spectrum between clean and completely unmaintainable, so do tests.

[sonofaplum]

Test save you time (maybe) in the long run. But in the search for product market fit, you may conceptualize, design, build, release and then scrap a feature within the course of a month. That's not a long enough lifespan for the tests ROI (better code, fewer bugs, better architecture) to be positive.

[spc476]

The regression test [1] for our legacy application takes five hours to run. It takes five hours to run because it also needs to check every log message (via syslog) to ensure every transaction happened.

I can't say it saves any time, and it certainly does not have a negative cost.

[1] There are no unit tests, as there are no real "units" to test. It's a legacy code base of C and C++, using a proprietary library that no one left in the company has much experience with. Said proprietary library is considered "legacy" by the company that owns it. I've seen the code. No wonder they consider it "legacy" (it started life in the mid-80s and god does it show).