Reduce flakeyness of Security3630Test

[das7pad]

I've hit a flakey run on Linux from Security3630Test.testHashMap on #26871 .

jenkins/test/src/test/java/hudson/cli/Security3630Test.java

Line 89 in 9878d67

void testHashMap() throws InterruptedException, IOException {

https://ci.jenkins.io/job/Core/job/jenkins/job/PR-26871/2/testReport/hudson.cli/Security3630Test/linux_jdk21___Linux___JDK_21___Build___Test___testHashMap/
java.io.IOException: java.util.concurrent.TimeoutException: Idle timeout expired: 30000/30000 ms

#26068 is another PR that hit a flakey run there.

It was very flakey on Windows and turned off there: jenkins-infra/helpdesk#4904 / #25927.

Running it locally takes more than 6min (and finishes with success). It might be worth looking into a "cheaper" way to test the hash map change that is less error prone.

cc @daniel-beck

[codingkiddo]

Hi, I would like to take a look at this.

I recently worked on a Jenkins core test reliability cleanup in QueueTest, replacing sleep-based waits with Awaitility-based condition polling: #26786

This issue looks related in spirit, so I will first try to reproduce the failure locally and understand the current test behavior before proposing a change.

Thanks.