org.junit.runners.model.InvalidTestClassError: 
Invalid test class 'org.jenkinsci.plugins.prometheus.collectors.jobs.BuildDiscardGaugeTest':
  1. Method testCollectResult() should be public
	at org.mockito.internal.runners.DefaultInternalRunner$1.<init>(DefaultInternalRunner.java:31)
	at org.mockito.internal.runners.DefaultInternalRunner.<init>(DefaultInternalRunner.java:30)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
	at org.mockito.internal.runners.util.RunnerProvider.newInstance(RunnerProvider.java:29)
	at org.mockito.internal.runners.RunnerFactory.create(RunnerFactory.java:75)
	at org.mockito.internal.runners.RunnerFactory.createStrict(RunnerFactory.java:40)
	at org.mockito.junit.MockitoJUnitRunner.<init>(MockitoJUnitRunner.java:154)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
	at java.base/java.util.ArrayList$ArrayListSpliterator.tryAdvance(ArrayList.java:1632)
	at java.base/java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:127)
	at java.base/java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:502)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:488)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
	at java.base/java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:150)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:543)