Skip slow tests on Travis

[bukka]

Travis jobs often fails due to not completing in 50 minutes. When it's successful, it's very close to 50 minutes so we need to do something about reducing the time of tests of travis. The most effective option should be to skip all slow tests which is probably fine on travis as it's just for s390x arch which is primarily to test a big endian so missing out on few slow tests should be hopefully fine...

[iluuu1994]

Hmm, these tests started failing on master on Travis a while ago. #10738 I'm not familiar with gz so I never figured out the cause.

[bukka]

shouldn't you put XFAIL on them rather than SKIP...

[bukka]

I will merge this as it just surfaced an issue but at least it now runs all tests.

[iluuu1994]

@bukka XFAIL is fine, it's just kinda useless (as it wastes CI time but doesn't really add anything).

[bukka]

yeah but it marks test as having potentially issue that might need to be investigated. But I see that you also created an issue for that so it's fine

[iluuu1994]

Right. It would be more useful if CI failed if XFAIL succeeds, as it only warns and people rarely look at the CI output of succeeded jobs it's not very helpful. This would require writing more precise SKIPIF sections, but that would likely be a good thing.

[bukka]

Some XFAIL tests are actually flaky which I think is ok because one might not need to spend too much time to investigate XFAIL. I think the useful think about XFAIL is that it's listed in CI output compare to skip ones. So if something is skipped, it will more likely get forgotten. But if there's also GH issue which is ideal case, then it's fine I think.

[iluuu1994]

I don't think XFAIL is a good solution for flaky tests, specifically because XFAIL emits a warning. If a bunch of tests warn, that makes it even less likely that a "previously failing, now passing" XFAIL test is discovered. I know added the FLAKY section which repeats the test if it fails.

I think the useful think about XFAIL is that it's listed in CI output compare to skip ones.

Yes, user indication is arguably the best part about xfail.