Fix flaky testItemOrder in ProgressViewTests

The test was failing randomly due to a race condition with the
ProgressViewerComparator's stable sorting mechanism (lastIndexes).

Root cause:
- The comparator maintains a HashMap of previous positions to provide
  visual stability (preventing jobs from jumping around in the UI)
- During test execution, throttled updates would occur while jobs were
  being scheduled, causing some jobs to be added to lastIndexes before
  others
- This resulted in an inconsistent baseline where jobs were sorted by
  schedule order rather than priority order

Fix:
- Reopen the progress view after all jobs are scheduled and running to
  reset the comparator's lastIndexes state
- This ensures all jobs are sorted by priority from a clean state,
  eliminating the race condition
- Removed the unreliable timing-based approach that tried to manipulate
  throttled updates

The test now passes reliably by working with the stable sorting
behavior rather than against it.

Fixes eclipse-platform#195

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: vogella

tests/org.eclipse.ui.tests/Eclipse UI Tests/org/eclipse/ui/tests/progress/ProgressViewTests.java

@@ -25,7 +25,6 @@
 import java.util.Collections;
 import java.util.concurrent.TimeUnit;
 
-import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.core.runtime.jobs.Job;
@@ -152,36 +151,49 @@ public void testItemOrder() throws Exception {
 //		allJobs.add(keptJob);
 
 		try {
+			// Set all jobs to not finish immediately so they stay running for comparison
+			for (DummyJob job : jobsToSchedule) {
+				job.shouldFinish = false;
+			}
+
+			// Close and reopen the progress view to get a fresh comparator with empty lastIndexes
+			hideProgressView();
+			openProgressView();
+
+			// Schedule all jobs in random order rapidly to minimize throttled updates between schedules
 			ArrayList<DummyJob> shuffledJobs = new ArrayList<>(jobsToSchedule);
 			Collections.shuffle(shuffledJobs);
 			StringBuilder scheduleOrder = new StringBuilder("Jobs schedule order: ");
-			progressView.getViewer().refresh(); // order will only hold on the first time.
-			Thread.sleep(200); // wait till throttled update ran.
-			Job dummyJob = new Job("dummy throttled caller") {
-				@Override
-				protected IStatus run(IProgressMonitor monitor) {
-					return Status.OK_STATUS;
-				}
-			};
-			dummyJob.schedule(); // trigger throttled update to clear ProgressViewerComparator.lastIndexes
-			// now hope the loop is executed before next throttled update (could fail if VM
-			// is busy otherwise):
 			for (DummyJob job : shuffledJobs) {
-				job.shouldFinish = false;
-				job.schedule(); // if the schedule updates the progress View (throttled) the sort order is
-								// affected
+				job.schedule();
 				scheduleOrder.append(job.getName()).append(", ");
 			}
 			TestPlugin.getDefault().getLog()
 					.log(new Status(IStatus.OK, TestPlugin.PLUGIN_ID, scheduleOrder.toString()));
 
+			// Wait for all jobs to be running
 			for (DummyJob job : allJobs) {
 				processEventsUntil(() -> job.inProgress, TimeUnit.SECONDS.toMillis(3));
 			}
-			progressView.getViewer().refresh();
+
+			// Wait for the progress view to be updated with all jobs
+			processEventsUntil(() -> progressView.getViewer().getProgressInfoItems().length == allJobs.size(),
+					TimeUnit.SECONDS.toMillis(5));
+
+			// The ProgressViewerComparator uses lastIndexes for stable sorting. After throttled updates
+			// during job scheduling, lastIndexes may contain jobs in schedule order rather than priority order.
+			// Close and reopen the view again to reset the comparator's state, then do a single refresh
+			// to sort all jobs by priority from a clean state.
+			hideProgressView();
+			openProgressView();
+
+			// Wait for the view to be populated again
 			processEventsUntil(() -> progressView.getViewer().getProgressInfoItems().length == allJobs.size(),
 					TimeUnit.SECONDS.toMillis(5));
 
+			// Give time for any pending updates
+			processEventsUntil(() -> false, 500);
+
 			ProgressInfoItem[] progressInfoItems = progressView.getViewer().getProgressInfoItems();
 			assertEquals("Not all jobs visible in progress view", allJobs.size(), progressInfoItems.length);
 			Object[] expected = allJobs.toArray();