HBASE-23241 TestExecutorService sometimes fail (apache#782)

Signed-off-by: Wellington Chevreuil <[email protected]>
(cherry picked from commit 2e05734)

Change-Id: Icd6e218036ef18f03573662398251181f7dc6878

Author: binlijin

hbase-server/src/test/java/org/apache/hadoop/hbase/executor/TestExecutorService.java

@@ -30,6 +30,7 @@
 import java.io.StringWriter;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import org.apache.hadoop.conf.Configuration;
@@ -231,9 +232,11 @@ public void testSnapshotHandlers() throws Exception {
     executorService.startExecutorService(ExecutorType.MASTER_SNAPSHOT_OPERATIONS, 1);
 
     CountDownLatch latch = new CountDownLatch(1);
+    CountDownLatch waitForEventToStart = new CountDownLatch(1);
     executorService.submit(new EventHandler(server, EventType.C_M_SNAPSHOT_TABLE) {
       @Override
       public void process() throws IOException {
+        waitForEventToStart.countDown();
         try {
           latch.await();
         } catch (InterruptedException e) {
@@ -242,9 +245,11 @@ public void process() throws IOException {
       }
     });
 
+    //Wait EventHandler to start
+    waitForEventToStart.await(10, TimeUnit.SECONDS);
     int activeCount = executorService.getExecutor(ExecutorType.MASTER_SNAPSHOT_OPERATIONS)
         .getThreadPoolExecutor().getActiveCount();
-    Assert.assertEquals(activeCount, 1);
+    Assert.assertEquals(1, activeCount);
     latch.countDown();
     Waiter.waitFor(conf, 3000, () -> {
       int count = executorService.getExecutor(ExecutorType.MASTER_SNAPSHOT_OPERATIONS)