Extension to execute test multiple times in parallel

[Bukama]

In one of our apps at work we recognized an error which somehow/sometimes happens when executing it in paralell. To be exactly it's an app with an REST-API and the error occurs sometimes, when it's called multiple times in short interval.

While trying to reproduce the error and writing a test for it a team mate asked me if I know a way to execute the same JUnit test multiple ties in parallel. But by default there is no way to do this. JUnit by itself only allows to configure execute test(classes) in parallel or as a sequence (see JUnit Userguide 2.19).

For the exact need of calling a REST-API (or other forms of webservice) we found the zerocode extension, but we don't like the way tests are configured. Before we found that, my first thought was "one could write a JUnit extension for that". And well here's the bishue :D

My idea would be an annotation like @ParallelExecution with an parameter for the number of parallel executions. The extension then runs the test multiple times, similar to the RetryingTest extesion.

@Test
@ParallelExectution(5)
void fiveTimesInParallel() {
  // test code
}

[Michael1993]

I've been thinking about this the last couple of days. Unfortunately I'm not really familiar with the multithreading in Java. 😔
I've been reading up a bit and I think I might have an idea. Will try a draft this weekend hopefully 🙏

[Michael1993]

I have something that I have no idea how to test. 😅

But if it works then it was a lot easier then I expected, since I can just let JUnit execute the tests in parallel for me - no multithreading knowledge required...?

[beatngu13]

I assume such an extension would also require some kind of "special" setup and/or TestInstance.Lifecycle, since one doesn't want the class under test to be reinstantiated during the parallel execution?

[nipafx]

Hey @Michael1993 , you wanna let us know about the magic implementation you came up with? 🧐

[Michael1993]

Hey @Michael1993 , you wanna let us know about the magic implementation you came up with? 🧐

Yeah, it was me being dumb again, sorry. 😓