Can i run Junit dynamic tests produced by @TestFactory concurrently?

Denis :

i am using the Discovering Tests feature of Junit and i also have a class that introduces a few @TestFactory methods each of which produces a great amount of dynamic tests. My first thought was "It would be great to be able to run these concurrently.", so i added

.configurationParameter(
               "junit.jupiter.execution.parallel.enabled", "true"
           )

to my LauncherDiscoveryRequestBuilder and i annotated my test class holding the factories with @Execution(ExecutionMode.CONCURRENT). So far so good, but i ended up with each @TestFactory method being run on a different thread but all the dynamic tests produced by a single @TestFactory share the same thread (the thread the @TestFactory that produced these tests runs on).

My question is - can i run the dynamic tests produced by a @TestFactory in parallel ? Also tried this

@TestFactory
@Execution(ExecutionMode.CONCURRENT)

but the result was the same.

Sam Brannen :

Yes, you can execute dynamic tests concurrently.

Here's a modified version of the dynamicNodeSingleContainer() test factory from the JUnit 5 User Guide

@TestFactory
@Execution(ExecutionMode.CONCURRENT)
DynamicNode dynamicNodeSingleContainer() {
    return dynamicContainer("palindromes",
        Stream.of("racecar", "radar", "mom", "dad")
            .map(text -> dynamicTest(text, () -> {
                assertTrue(isPalindrome(text));
                System.err.println(Thread.currentThread().getName());
            })
    ));
}

When I execute it, I see the following output which demonstrates that the 4 dynamic tests executed concurrently in different threads.

ForkJoinPool-1-worker-5
ForkJoinPool-1-worker-11
ForkJoinPool-1-worker-7
ForkJoinPool-1-worker-9