try add a test

Signed-off-by: tison <wander4096@gmail.com>

curator-recipes/pom.xml

@@ -83,6 +83,12 @@
             <scope>test</scope>
         </dependency>
 
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+
         <dependency>
             <groupId>org.awaitility</groupId>
             <artifactId>awaitility</artifactId>

curator-recipes/src/test/java/org/apache/curator/framework/recipes/leader/TestLeaderLatch.java

@@ -19,6 +19,7 @@
 
 package org.apache.curator.framework.recipes.leader;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNull;
@@ -52,6 +53,7 @@
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
+import javax.annotation.Nonnull;
 import org.apache.curator.framework.CuratorFramework;
 import org.apache.curator.framework.CuratorFrameworkFactory;
 import org.apache.curator.framework.imps.TestCleanState;
@@ -72,9 +74,12 @@
 import org.awaitility.Awaitility;
 import org.junit.jupiter.api.Tag;
 import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 @Tag(CuratorTestBase.zk35TestCompatibilityGroup)
 public class TestLeaderLatch extends BaseClassForTests {
+    private static final Logger LOG = LoggerFactory.getLogger(TestLeaderLatch.class);
     private static final String PATH_NAME = "/one/two/me";
     private static final int MAX_LOOPS = 5;
 
@@ -208,6 +213,59 @@ public void testWatchedNodeDeletedOnReconnect() throws Exception {
         }
     }
 
+    @Test
+    public void testSessionInterruptionDoNotCauseBrainSplit() throws Exception {
+        final String latchPath = "/testSessionInterruptionDoNotCauseBrainSplit";
+        final Timing2 timing = new Timing2();
+        final BlockingQueue<TestEvent> events = new LinkedBlockingQueue<TestEvent>() {
+            @Override
+            public boolean add(@Nonnull TestEvent testEvent) {
+                LOG.debug("Add event: {}", testEvent);
+                return super.add(testEvent);
+            }
+        };
+
+        final List<Closeable> closeableResources = new ArrayList<>();
+        try {
+            final String id0 = "id0";
+            final CuratorFramework client0 = createAndStartClient(server.getConnectString(), timing, id0, null);
+            closeableResources.add(client0);
+            final LeaderLatch latch0 = createAndStartLeaderLatch(client0, latchPath, id0, events);
+            closeableResources.add(latch0);
+
+            assertThat(events.poll(timing.forWaiting().milliseconds(), TimeUnit.MILLISECONDS))
+                    .isNotNull()
+                    .isEqualTo(new TestEvent(id0, TestEventType.GAINED_LEADERSHIP));
+
+            final String id1 = "id1";
+            final CuratorFramework client1 = createAndStartClient(server.getConnectString(), timing, id1, null);
+            closeableResources.add(client1);
+            final LeaderLatch latch1 = createAndStartLeaderLatch(client1, latchPath, id1, events);
+            closeableResources.add(latch1);
+
+            // wait for the non-leading LeaderLatch (i.e. latch1) instance to be done with its creation
+            // this call is time-consuming but necessary because we don't have a handle to detect the end of the reset
+            // call
+            timing.forWaiting().sleepABit();
+
+            assertTrue(latch0.hasLeadership());
+            assertFalse(latch1.hasLeadership());
+
+            client0.getZookeeperClient().getZooKeeper().getTestable().injectSessionExpiration();
+
+            assertThat(events.poll(timing.forWaiting().milliseconds(), TimeUnit.MILLISECONDS))
+                    .isNotNull()
+                    .isEqualTo(new TestEvent(id0, TestEventType.LOST_LEADERSHIP));
+            assertThat(events.poll(timing.forWaiting().milliseconds(), TimeUnit.MILLISECONDS))
+                    .isNotNull()
+                    .isEqualTo(new TestEvent(id1, TestEventType.GAINED_LEADERSHIP));
+        } finally {
+            // reverse is necessary for closing the LeaderLatch instances before closing the corresponding client
+            Collections.reverse(closeableResources);
+            closeableResources.forEach(CloseableUtils::closeQuietly);
+        }
+    }
+
     @Test
     public void testResettingOfLeadershipAfterConcurrentLeadershipChange() throws Exception {
         final String latchPath = "/test";
@@ -316,7 +374,9 @@ private static CuratorFramework createAndStartClient(
 
         client.getConnectionStateListenable().addListener((client1, newState) -> {
             if (newState == ConnectionState.CONNECTED) {
-                events.add(new TestEvent(id, TestEventType.GAINED_CONNECTION));
+                if (events != null) {
+                    events.add(new TestEvent(id, TestEventType.GAINED_CONNECTION));
+                }
             }
         });
 
@@ -366,6 +426,11 @@ public boolean equals(Object o) {
             TestEvent testEvent = (TestEvent) o;
             return Objects.equals(id, testEvent.id) && eventType == testEvent.eventType;
         }
+
+        @Override
+        public String toString() {
+            return "TestEvent{" + "eventType=" + eventType + ", id='" + id + '\'' + '}';
+        }
     }
 
     @Test