Stacktrace on STDOUT/STDERR on CI/CD

Using Gradle 4.1 I’m working on a CI/CD that is currently configured to provide downloads of artifacts only after test pass sucessfully.
Unfortunately I have a (JUnit) test which fails only on the CI/CD and for which I get only something like

com.acme.MyClassTest > fancyTest FAILED
java.lang.AssertionError

which is not really useful because of the missing message and stacktrace…

I tried to configure something more with:

import org.gradle.api.tasks.testing.logging.TestExceptionFormat
import org.gradle.api.tasks.testing.logging.TestStackTraceFilter
tasks.withType(Test) {
	testLogging {
		showExceptions              true
		showStackTraces             true
		showCauses                  true

		exceptionFormat             TestExceptionFormat.FULL
		stackTraceFilters           TestStackTraceFilter.ENTRY_POINT
	}
}

but it doesn’t seem to give me any change regarding the output