diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestFairSchedulerPreemption.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestFairSchedulerPreemption.java
index 59d243bc690..31630240e28 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestFairSchedulerPreemption.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestFairSchedulerPreemption.java
@@ -24,6 +24,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.scheduler.event.NodeUpdateS
 import org.apache.hadoop.yarn.server.resourcemanager.rmcontainer.RMContainer;
 import org.apache.hadoop.yarn.server.resourcemanager.rmcontainer.RMContainerImpl;
 import org.apache.hadoop.yarn.util.ControlledClock;
+import org.apache.hadoop.yarn.util.SystemClock;
 import org.junit.After;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -188,6 +189,9 @@ public class TestFairSchedulerPreemption extends FairSchedulerTestBase {
   private void setupCluster() throws IOException {
     resourceManager = new MockRM(conf);
     scheduler = (FairScheduler) resourceManager.getResourceScheduler();
+    // YARN-6249, FSLeafQueue#lastTimeAtMinShare is initialized to the time in
+    // the real world, so we should keep the clock up with it.
+    clock.setTime(SystemClock.getInstance().getTime());
     scheduler.setClock(clock);
     resourceManager.start();