Cannot run tests -- tests don't run + play button gets disabled

I'm trying to run a Quarkus test (JUnit5):

* https://github.com/Apicurio/apicurio-registry/blob/master/app/src/test/java/io/apicurio/registry/ConfluentClientTest.java

For an unknown reason the test doesn't run, and afterwards the "play" button is disabled.

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IDEA: CE 2018.1.8 / 181.5684.4

JDK: 1.8.0_152-release-1136-b43

Any idea where I could look for some log or some more info on what is wrong?

Or did anyone seen this before?

Tnx!

-Ales