TSK-1757: Added ParallelThreadHelper to support multi threaded tests.

common/taskana-common-test/src/main/java/pro/taskana/common/test/util/ParallelThreadHelper.java

@@ -0,0 +1,30 @@
+package pro.taskana.common.test.util;
+
+import java.lang.Thread.UncaughtExceptionHandler;
+import java.util.Collection;
+import java.util.concurrent.ConcurrentLinkedQueue;
+
+import pro.taskana.common.api.exceptions.SystemException;
+
+public class ParallelThreadHelper {
+
+  public static void runInThread(Runnable runnable, int threadCount) throws Exception {
+    Thread[] threads = new Thread[threadCount];
+
+    Collection<Throwable> errors = new ConcurrentLinkedQueue<>();
+    UncaughtExceptionHandler uncaughtExceptionHandler = (t, e) -> errors.add(e);
+
+    for (int i = 0; i < threads.length; i++) {
+      threads[i] = new Thread(runnable);
+      threads[i].setUncaughtExceptionHandler(uncaughtExceptionHandler);
+      threads[i].start();
+    }
+    for (Thread thread : threads) {
+      thread.join();
+    }
+    if (!errors.isEmpty()) {
+      errors.forEach(Throwable::printStackTrace);
+      throw new SystemException("at least 1 thread caught an exception.");
+    }
+  }
+}

lib/taskana-core/src/test/java/acceptance/jobs/JobRunnerAccTest.java

@@ -22,6 +22,7 @@ import pro.taskana.common.internal.JobServiceImpl;
 import pro.taskana.common.internal.jobs.JobRunner;
 import pro.taskana.common.internal.jobs.PlainJavaTransactionProvider;
 import pro.taskana.common.test.config.DataSourceGenerator;
+import pro.taskana.common.test.util.ParallelThreadHelper;
 import pro.taskana.task.internal.jobs.TaskCleanupJob;
 
 @Disabled
@@ -37,7 +38,7 @@ class JobRunnerAccTest extends AbstractAccTest {
     ScheduledJob job = createJob(Instant.now().minus(5, ChronoUnit.MINUTES));
     assertThat(jobService.findJobsToRun()).containsExactly(job);
 
-    runInThread(
+    ParallelThreadHelper.runInThread(
         () -> {
           try {
             TaskanaEngine taskanaEngine =
@@ -69,17 +70,6 @@ class JobRunnerAccTest extends AbstractAccTest {
     assertThat(jobsToRun).hasSize(1).doesNotContain(job);
   }
 
-  private void runInThread(Runnable runnable, int threadCount) throws Exception {
-    Thread[] threads = new Thread[threadCount];
-    for (int i = 0; i < threads.length; i++) {
-      threads[i] = new Thread(runnable);
-      threads[i].start();
-    }
-    for (Thread thread : threads) {
-      thread.join();
-    }
-  }
-
   private ScheduledJob createJob(Instant firstDue) {
     ScheduledJob job = new ScheduledJob();
     job.setType(TaskCleanupJob.class.getName());

lib/taskana-core/src/test/java/acceptance/task/SelectAndClaimTaskAccTest.java

@@ -22,6 +22,7 @@ import pro.taskana.common.api.security.UserPrincipal;
 import pro.taskana.common.internal.util.CheckedConsumer;
 import pro.taskana.common.test.security.JaasExtension;
 import pro.taskana.common.test.security.WithAccessId;
+import pro.taskana.common.test.util.ParallelThreadHelper;
 import pro.taskana.task.api.TaskQuery;
 import pro.taskana.task.api.TaskService;
 import pro.taskana.task.api.models.Task;
@@ -39,7 +40,8 @@ class SelectAndClaimTaskAccTest extends AbstractAccTest {
             Stream.of("admin", "teamlead-1", "teamlead-2", "taskadmin")
                 .collect(Collectors.toList()));
 
-    runInThread(getRunnableTest(selectedAndClaimedTasks, accessIds), accessIds.size());
+    ParallelThreadHelper.runInThread(
+        getRunnableTest(selectedAndClaimedTasks, accessIds), accessIds.size());
 
     assertThat(selectedAndClaimedTasks)
         .extracting(Task::getId)
@@ -67,17 +69,6 @@ class SelectAndClaimTaskAccTest extends AbstractAccTest {
                 + "task query returned nothing!");
   }
 
-  private void runInThread(Runnable runnable, int threadCount) throws InterruptedException {
-    Thread[] threads = new Thread[threadCount];
-    for (int i = 0; i < threads.length; i++) {
-      threads[i] = new Thread(runnable);
-      threads[i].start();
-    }
-    for (Thread thread : threads) {
-      thread.join();
-    }
-  }
-
   private Runnable getRunnableTest(List<Task> selectedAndClaimedTasks, List<String> accessIds) {
     return () -> {
       Subject subject = new Subject();