Flaky streaming test

[gvolpe]

dev.profunktor.redis4cats.RedisStreamSpec:
==> X dev.profunktor.redis4cats.RedisStreamSpec.append/read to/from a stream  3.219s java.util.NoSuchElementException: null
    at fs2.Stream$CompileOps.$anonfun$lastOrError$3(Stream.scala:4329)
    at scala.Option.fold(Option.scala:251)
    at fs2.Stream$CompileOps.$anonfun$lastOrError$2(Stream.scala:4329)

https://github.com/profunktor/redis4cats/runs/1805553054?check_suite_focus=true

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[gvolpe]

Still seeing this

dev.profunktor.redis4cats.RedisStreamSpec:
==> X dev.profunktor.redis4cats.RedisStreamSpec.append/read to/from a stream  3.212s java.util.NoSuchElementException: null
    at fs2.Stream$CompileOps.$anonfun$lastOrError$3(Stream.scala:4401)
    at scala.Option.fold(Option.scala:251)
    at fs2.Stream$CompileOps.$anonfun$lastOrError$2(Stream.scala:4401)

[wiwa]

I was playing around with this. Somehow, setting the read to block = Some(1.millis) removes the flakiness (tested via 100+ runs). This doesn't make sense to me, since the default is block = Some(Duration.Zero), i.e. wait forever.

If we use N messages instead of 1, and say interruptAfter(1000.seconds), then .take(N - 1) makes it "work", while .take(N) leads to hanging forever.

Question: why is there a repeat here?

redis4cats/modules/streams/src/main/scala/dev/profunktor/redis4cats/streams/Fs2Streaming.scala

Line 97 in 296b6fe

} yield result).repeat

[gvolpe]

I was playing around with this. Somehow, setting the read to block = Some(1.millis) removes the flakiness (tested via 100+ runs). This doesn't make sense to me, since the default is block = Some(Duration.Zero), i.e. wait forever.

Fixes that require a sleep or so are really flaky, that's why this test is marked as such.

If we use N messages instead of 1, and say interruptAfter(1000.seconds), then .take(N - 1) makes it "work", while .take(N) leads to hanging forever.

Does take(N - 1) get you all the published messages? I think that would be missing the final message, no?

Question: why is there a repeat here?

I can't remember any details of the streaming module, it's been too long, but since you seem to have it fresh I'll counter-ask, why shouldn't there be a repeat there? :)