@mrkz it's very nice if you can do it; but it can be tricky if your test harnesses being in lots of extra build dependencies or really push the time up; and those tests had better be *really* stable otherwise they'll annoy the package builder. Similarly a lot of package build environments don't allow external connectivity.
I'll tell you about my brief experience with Guix:
tests are deemed important, but it is acknowledged that sometimes they fail for spurious reasons
If you exclude the tests in a package you contribute, you'll be asked why and your reasons for excluding them will be considered
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