alt Hacker NewsThis feels like the image of the plane that returns from battle with bullet holes, and the engineer being asked to path up where the holes to make it stronger. Only to be told to patch where there weren't holes as those planes didn't make it home.
While not an exact fit of an analogy, those tests patch what was a problem with Postgres in the wild. What it doesn't cover are the things that worked in Postgres without tests, but may fail in port and go undetected.
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win311fwg • today at 8:36 AM
Anything that doesn't have tests is unspecified behaviour. While it is true that a port may differ in behaviour where the behaviour is unspecified, "fail" is not the right framing as there is no definition of what it should do.
I don't necessarily disagree, but two other points to consider:
1. Every test that is written is another use case that wasn't tested before. 100% test coverage is often impractical, but the more tests you have the more of the code you can be confident about.
2. Every test you add is another regression that can't happen in the future; if you test the index rebuilding code and validate the output then you know that you aren't going to make a change that breaks the index rebuilding code. If you have a legitimate change you update the tests, but if you're not expecting the change then you know there's a bug somewhere.