RxScala: Update CompletenessTest.scala

[zsxwing]

Cleaned up CompletenessTest.scala.

onBackpressureBuffer and onBackpressureDrop are missing in RxScala now. Wait until they are finalized in RxJava.

/cc @headinthebox, @samuelgruetter

[cloudbees-pull-request-builder]

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[headinthebox]

Thanks @zsxwing.

Would there be a way to make this code less "stringlytyped" and use reflection or something instead of manually maintaining a list of signatures.

[benjchristensen]

Is this ready to merge, or is there more to do based on the last comment by @headinthebox ?

[headinthebox]

I think you can merge; we can discuss alternatives in an issue.

[samuelgruetter]

Would there be a way to make this code less "stringlytyped" and use reflection or something instead of manually maintaining a list of signatures.

We already use reflection to generate the defaultMethodCorrespondence, which contains all "obvious" Java->Scala mappings which can be obtained through mechanical changes such as replacing Func1[T, U] by T => U or Long, TimeUnit by Duration. The mappings in correspondenceChanges only contain deviations from the obvious default correspondence, and override the auto-generated default correspondence. I see no other solution than maintaining the correspondenceChanges list manually.

We also use reflection to check that the methods mentioned in correspondenceChanges actually exist: checkJavaMethodPresence and checkScalaMethodPresence report all mentioned methods which do not exist. So it's still "stringlytyped", but we have a "typechecker" for it ;-)

I agree that this code still looks too "stringlytyped" and that one would also want to use reflection to write down the correspondenceChanges list. I've tried this, but I abandoned it because it became very verbose and unreadable.

[samuelgruetter]

LGTM