LockRegistryLeaderInitiatorTests race condition

There is tiny time window when `LockRegistryLeaderInitiator` can be stopped during `Context.yield()` invocation.
In this case the `LockRegistryLeaderInitiator` goes to the stopped state, but a new `leaderSelector` is submitted for election.

Therefore in the `LockRegistryLeaderInitiatorTests.competing()` the second initiator may not get be granted because there is uncontrolled `leaderSelector` task on background.

We can overcome it with always `this.initiator.stop()` for the `LockRegistryLeaderInitiatorTests`, but to be sure in the fix it would be better to leave as is.

Also add `@Rule Log4jLevelAdjuster` for future diagnostics

**Cherry-pick to 4.3.x**

spring-integration-core/src/main/java/org/springframework/integration/support/leader/LockRegistryLeaderInitiator.java

@@ -200,7 +200,9 @@ public class LockRegistryLeaderInitiator implements SmartLifecycle, DisposableBe
 	 */
 	@Override
 	public boolean isRunning() {
-		return this.running;
+		synchronized (this.lifecycleMonitor) {
+			return this.running;
+		}
 	}
 
 	@Override
@@ -399,9 +401,11 @@ public class LockRegistryLeaderInitiator implements SmartLifecycle, DisposableBe
 		public void yield() {
 			if (LockRegistryLeaderInitiator.this.future != null) {
 				LockRegistryLeaderInitiator.this.future.cancel(true);
-				LockRegistryLeaderInitiator.this.future =
+				if (isRunning()) {
-						LockRegistryLeaderInitiator.this.executorService
+					LockRegistryLeaderInitiator.this.future =
-								.submit(LockRegistryLeaderInitiator.this.leaderSelector);
+							LockRegistryLeaderInitiator.this.executorService
+									.submit(LockRegistryLeaderInitiator.this.leaderSelector);
+				}
 			}
 		}
 

spring-integration-core/src/test/java/org/springframework/integration/support/leader/LockRegistryLeaderInitiatorTests.java

@@ -22,7 +22,9 @@ import static org.junit.Assert.assertThat;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 
+import org.apache.log4j.Level;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
 
 import org.springframework.integration.leader.Context;
@@ -30,27 +32,33 @@ import org.springframework.integration.leader.DefaultCandidate;
 import org.springframework.integration.leader.event.LeaderEventPublisher;
 import org.springframework.integration.support.locks.DefaultLockRegistry;
 import org.springframework.integration.support.locks.LockRegistry;
+import org.springframework.integration.test.rule.Log4jLevelAdjuster;
 
 /**
  * @author Dave Syer
+ * @author Artem Bilan
+ *
  * @since 4.3.1
  */
 public class LockRegistryLeaderInitiatorTests {
 
-	private CountDownLatch granted = new CountDownLatch(1);
+	@Rule
+	public Log4jLevelAdjuster adjuster = new Log4jLevelAdjuster(Level.TRACE, "org.springframework.integration");
 
-	private CountDownLatch revoked = new CountDownLatch(1);
+	private CountDownLatch granted;
+
+	private CountDownLatch revoked;
 
 	private LockRegistry registry = new DefaultLockRegistry();
 
-	private CountingPublisher publisher = new CountingPublisher(this.granted, this.revoked);
-
 	private LockRegistryLeaderInitiator initiator =
 			new LockRegistryLeaderInitiator(this.registry, new DefaultCandidate());
 
 	@Before
 	public void init() {
-		this.initiator.setLeaderEventPublisher(this.publisher);
+		this.granted = new CountDownLatch(1);
+		this.revoked = new CountDownLatch(1);
+		this.initiator.setLeaderEventPublisher(new CountingPublisher(this.granted, this.revoked));
 	}
 
 	@Test