ci: add NeonBeeTestExecutionListener to check for stale threads

build.gradle

@@ -100,6 +100,7 @@ dependencies {
 
     // Required for Eclipse to run Unit tests.
     testImplementation group: 'org.junit.platform', name: 'junit-platform-commons', version: '1.7.0'
+    testImplementation group: 'org.junit.platform', name: 'junit-platform-launcher', version: '1.7.0'
 
     // Gradle plugin dependencies
     errorprone group: 'com.google.errorprone', name: 'error_prone_core', version: '2.5.1'

src/test/java/io/neonbee/NeonBeeTestExecutionListener.java

@@ -0,0 +1,51 @@
+package io.neonbee;
+
+import java.util.Optional;
+
+import org.junit.platform.engine.TestExecutionResult;
+import org.junit.platform.launcher.TestExecutionListener;
+import org.junit.platform.launcher.TestIdentifier;
+import org.junit.platform.launcher.TestPlan;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * The {@link NeonBeeTestExecutionListener} checks for any stale Vert.x threads after test execution. Generally after a
+ * test finishes to execute it must clean up all Vert.x resources. If not this listener will print an error to the logs.
+ */
+public class NeonBeeTestExecutionListener implements TestExecutionListener {
+    private static final Logger LOGGER = LoggerFactory.getLogger(TestExecutionListener.class);
+
+    private boolean parallelExecution;
+
+    @Override
+    public void testPlanExecutionStarted(TestPlan testPlan) {
+        parallelExecution = "true".equalsIgnoreCase(System.getProperty("junit.jupiter.execution.parallel.enabled"));
+        if (parallelExecution) {
+            LOGGER.warn("Cannot check for stale threads when running JUnit in parallel execution mode");
+        }
+    }
+
+    @Override
+    public void executionFinished(TestIdentifier testIdentifier, TestExecutionResult testExecutionResult) {
+        if (!parallelExecution) {
+            checkForStaleThreads("Vert.x", "vert.x-");
+            checkForStaleThreads("Hazelcast", "hz.");
+            checkForStaleThreads("WatchService", "FileSystemWatch");
+        }
+    }
+
+    private static void checkForStaleThreads(String title, String namePrefix) {
+        LOGGER.info("Checking for stale {} threads with '{}' prefix", title, namePrefix);
+        Optional<Thread> staleThread = findStaleThread(namePrefix);
+        if (staleThread.isPresent() && LOGGER.isErrorEnabled()) {
+            LOGGER.error("Stale {} thread(s) detected!! Not closing the thread {} "
+                    + "could result in the test runner not signaling completion", title, staleThread.get());
+        }
+    }
+
+    private static Optional<Thread> findStaleThread(String namePrefix) {
+        return Thread.getAllStackTraces().keySet().stream().filter(thread -> thread.getName().startsWith(namePrefix))
+                .findAny();
+    }
+}

src/test/resources/META-INF/services/org.junit.platform.launcher.TestExecutionListener

@@ -0,0 +1 @@
+io.neonbee.NeonBeeTestExecutionListener