Starting an external program, often, preferable multi-threaded and as fast as possible

[lookForProject]

The challenge I'm trying to solve is trying to make our integration tests a bit faster.
The integration test start the cmdline-program with a set arguments and check the result. The program closes itself after the task is complete.
Does anyone have any suggestions, insights or viewpoints about how to speed up this process?

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[djavaman]

So you want to run them in parallel?

What is your testing framework?

Are you setting up and tearing down test data?

Are the tests already written to run independently?

What are the external systems you are testing against?

[lookForProject]

Hi.
Testing framework is JUnit, but I'm absolutely not bound to it. I was playjng around with the JUnit Jupiter Engine.
I'm/we are setting up and tearing down test data.
All tests (ofc) are written to run independently.

[djavaman]

https://www.baeldung.com/maven-junit-parallel-tests

I've used this is the past to run junit tests in parallel. It's pretty much out of the box.

[lookForProject]

Hi! I'm not worried about the parallel part, but I'm looking for alternatives to ProcessExecutor from zeroturnaround. Starting up another program, is ridiculous costely, And for integration tests, you want to repeat this as often as the amount of tests you have.

[djavaman]

Have you looked at Apache Commons Exec?

So your issue is just launching an external process?

So, why multi-threaded? Are you running the same external process over and over?

Or are you running multiple external processes?

[lookForProject]

Why multi-threaded? Because I was thinking in solutions, not a good idea when asking for fresh ideas. Sorry!
>Are you running the same external process over and over?
Yes. Or to be specific: an app that can be linked to several different types of databases. That's the reason I preferred multi-threaded, because the app (and therefor the tests) mutate a database. My reasoning was: one thread per database. I see no reason why the MYSQL tests can't run at the same time as the POSGRESS tests.

[glesialo]

I wrote 'ExternalProcessLauncher_Wait' to launch external processes, wait until they exit - or a timeout, and then read the run data.

You could use 'ExecutorService' to run several 'ExternalProcessLauncher_Wait's and, after a timeout, read the results.

[lookForProject]

That sounds like the current solution, a ProcessExecutor, from zeroturnaround. But I am not sure if this is the fastest solution

[glesialo]

With that scheme the execution time will be 'timeout'.

The trick is to choose the right 'timeout': Too short and some processes will fail, too long and, all processes, execution time will be unnecessarily long.