Avoid race conditions by waiting for the log before creating the second consumer.

Author: jeanouii

activemq-unit-tests/src/test/java/org/apache/activemq/usecases/UsageBlockedDispatchTest.java

@@ -26,6 +26,7 @@
 import org.apache.activemq.command.ActiveMQQueue;
 import org.apache.activemq.usage.SystemUsage;
 import org.apache.activemq.util.DefaultTestAppender;
+import org.apache.activemq.util.Wait;
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.core.LogEvent;
@@ -154,6 +155,8 @@ public void append(LogEvent event) {
 
         try {
 
+            assertTrue("Timed out waiting for cursor to block", Wait.waitFor(() -> gotExpectedLogEvent.get()));
+
             MessageConsumer noDispatchConsumer = consumerSession.createConsumer(shouldBeStuckForDispatch);
 
             Message m = noDispatchConsumer.receive(messageReceiveTimeout);