From 15c45d2029af722b3e724b3e99f95b2930f8690e Mon Sep 17 00:00:00 2001
From: Joshua Kim <kimjos@amazon.com>
Date: Mon, 27 Jul 2020 19:17:27 -0400
Subject: [PATCH] Adding a unit test

---
 .../kinesis/leases/LeaseCleanupManager.java    | 18 ++++++++++--------
 .../leases/LeaseCleanupManagerTest.java        | 11 +++++++++++
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/amazon-kinesis-client/src/main/java/software/amazon/kinesis/leases/LeaseCleanupManager.java b/amazon-kinesis-client/src/main/java/software/amazon/kinesis/leases/LeaseCleanupManager.java
index b725696c..0fb9ccd6 100644
--- a/amazon-kinesis-client/src/main/java/software/amazon/kinesis/leases/LeaseCleanupManager.java
+++ b/amazon-kinesis-client/src/main/java/software/amazon/kinesis/leases/LeaseCleanupManager.java
@@ -81,14 +81,16 @@ public class LeaseCleanupManager {
      * {@link LeaseCleanupManager#leaseCleanupIntervalMillis}
      */
     public void start() {
-        log.debug("Starting lease cleanup thread.");
-
-        completedLeaseStopwatch.start();
-        garbageLeaseStopwatch.start();
-
-        deletionThreadPool.scheduleAtFixedRate(new LeaseCleanupThread(), INITIAL_DELAY, leaseCleanupIntervalMillis,
-                TimeUnit.MILLISECONDS);
-        isRunning = true;
+        if (!isRunning) {
+            log.debug("Starting lease cleanup thread.");
+            completedLeaseStopwatch.reset().start();
+            garbageLeaseStopwatch.reset().start();
+            deletionThreadPool.scheduleAtFixedRate(new LeaseCleanupThread(), INITIAL_DELAY, leaseCleanupIntervalMillis,
+                    TimeUnit.MILLISECONDS);
+            isRunning = true;
+        } else {
+            log.debug("Lease cleanup thread already running, no need to start.");
+        }
     }
 
     /**
diff --git a/amazon-kinesis-client/src/test/java/software/amazon/kinesis/leases/LeaseCleanupManagerTest.java b/amazon-kinesis-client/src/test/java/software/amazon/kinesis/leases/LeaseCleanupManagerTest.java
index e9d237f9..02c71b03 100644
--- a/amazon-kinesis-client/src/test/java/software/amazon/kinesis/leases/LeaseCleanupManagerTest.java
+++ b/amazon-kinesis-client/src/test/java/software/amazon/kinesis/leases/LeaseCleanupManagerTest.java
@@ -15,6 +15,7 @@
 
 package software.amazon.kinesis.leases;
 
+import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -83,6 +84,16 @@ public class LeaseCleanupManagerTest {
         when(leaseCoordinator.updateLease(any(Lease.class), any(UUID.class), any(String.class), any(String.class))).thenReturn(true);
     }
 
+    /**
+     * Tests subsequent calls to start {@link LeaseCleanupManager}.
+     */
+    @Test
+    public final void testSubsequentStarts() {
+        leaseCleanupManager.start();
+        Assert.assertTrue(leaseCleanupManager.isRunning());
+        leaseCleanupManager.start();
+    }
+
     /**
      * Tests that when both child shard leases are present, we are able to delete the parent shard for the completed
      * shard case.