If I had a codebase with lots of tests and asked someone else to rewrite it to another language passing the same test suite, I honestly wouldn't expect a great quality job.
I say this because it happened 3 times in the company I work for: we conducted experiments by tasking different companies to rewrite the same code in another language. All of them passed (most) of the tests, but code quality was low. If the job is a black box, rely on the I/O to determine quality, not the inner workings.
There's no way this code is understood fully by the original author, let alone anyone else. I wouldn't accept this from an intern, let alone in code that's fundamental to my business.
Why?
Some of the patterns that I saw:
* The code is only called from tests but never called in production
* Tests are not testing the actual application logic, or the logic that matters. In some cases, the tests have nothing to do with the application code at all, because it does not even run any application code.
* Tests repeat the same logic as in application (tautology). All the time.
* Application code is actually incorrect. But tests just end up using the wrong expected value to make tests pass, disregarding what should happen.
That's using the latest models.
To make things better, apparently people never bothered to go through the manual workflow at least once to verify the behavior.
Good luck just relying on tests.
> it’s basically the same codebase except now we can have the compiler enforce the lifetimes of types and we get destructors when we want them. and the ugly parts look uglier (unsafe) which encourages refactoring.
> why: I am so tired of worrying about & spending lots of time fixing memory leaks and crashes and stability issues. it would be so nice if the language provided more powerful tools for preventing these things.
This makes me trust it more, not less.