YARN-6222. TestFairScheduler.testReservationMetrics is flaky. (Yufei Gu via kasha)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FSLeafQueue.java

@@ -407,8 +407,7 @@ public class FSLeafQueue extends FSQueue {
     readLock.lock();
     try {
       for (FSAppAttempt app : runnableApps) {
-        Resource pending = app.getAppAttemptResourceUsage().getPending();
-        if (!Resources.isNone(pending) &&
+        if (!Resources.isNone(app.getPendingDemand()) &&
             (assignment || app.shouldCheckForStarvation())) {
           pendingForResourceApps.add(app);
         }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestFairScheduler.java

@@ -5079,6 +5079,7 @@ public class TestFairScheduler extends FairSchedulerTestBase {
     scheduler.handle(updateEvent);
 
     createSchedulingRequestExistingApplication(1024, 1, 1, appAttemptId);
+    scheduler.update();
     scheduler.handle(updateEvent);
 
     // no reservation yet