Code Coverage Inline Function

Question

i have this function written in Kotlin

inline fun <T> handleEmptyResult(observable: Observable<T>,
                                 crossinline resultEmptyCheckingFunc: (obj: T?) -> Boolean): Observable<T> {
    return observable
        .flatMap {
            if (resultEmptyCheckingFunc(it)) {
                Observable.error<T>(ResultEmptyError(Throwable()))
            } else {
                Observable.just(it)
            }
        }
}

But when i created unit tests for this function, it shows 0 coverage on the report. I am using jacoco for code coverage. Do you guys know how to unit test inline function properly? Thanks!

This is a Kotlin bug, currently logged here: https://youtrack.jetbrains.com/issue/KT-12605 — Max, Nov 09 '17 at 17:24
Possible duplicate of [No coverage report for inlined Kotlin methods](https://stackoverflow.com/questions/39817814/no-coverage-report-for-inlined-kotlin-methods) — Manushin Igor, Nov 14 '17 at 17:43

score 0 · Accepted Answer · answered Jan 05 '17 at 08:04

0

Since the code is inlined, there are no calls to this function in your tests, and jacoco thinks that you never use it.

A piece of advice: forget about test coverage, it is totally useless. A project can have great tests and 30% coverage. Or someone can spend a ton of time to get 100% coverage, and still have dozens of bugs in production. I've seen both.

answered Jan 05 '17 at 08:04

voddan

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Ah I see, so that is the reason. Thanks for the advice @voddan – elsennov Jan 05 '17 at 08:06
13

The above response doesn't answer the question btw – joseph.rawlings May 26 '17 at 18:19
2

Still, coverage **is** good when it's unclear which code paths are used/covered and which are not, especially in legacy code. – Bass Mar 10 '21 at 14:27

Code Coverage Inline Function

1 Answers1