Guard tests against changing subscription order.

See #2143

Author: mp911de

src/test/java/org/springframework/data/redis/listener/RedisMessageListenerContainerIntegrationTests.java

@@ -16,6 +16,7 @@
 package org.springframework.data.redis.listener;
 
 import static org.assertj.core.api.Assertions.*;
+import static org.awaitility.Awaitility.*;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -207,8 +208,9 @@ public void onPatternSubscribed(byte[] pattern, long count) {
 		received.await(2, TimeUnit.SECONDS);
 		container.destroy();
 
-		assertThat(subscriptions1).hasValue(1);
-		assertThat(subscriptions2).hasValue(1);
+		await().until(() -> subscriptions1.get() > 0 || subscriptions2.get() > 0);
+
+		assertThat(subscriptions1.get() + subscriptions2.get()).isEqualTo(1);
 	}
 
 	interface CompositeListener extends MessageListener, SubscriptionListener {