diff --git a/apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/entity/ServerConfig.java b/apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/entity/ServerConfig.java
index 541ba6cb22d..d7a55d53959 100644
--- a/apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/entity/ServerConfig.java
+++ b/apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/entity/ServerConfig.java
@@ -79,6 +79,6 @@ public void setCluster(String cluster) {
 
   @Override
   public String toString() {
-    return toStringHelper().add("key", key).add("value", value).add("comment", comment).toString();
+    return toStringHelper().add("key", key).add("value", value).add("cluster", cluster).add("comment", comment).toString();
   }
 }
diff --git a/apollo-biz/src/test/java/com/ctrip/framework/apollo/biz/utils/ReleaseKeyGeneratorTest.java b/apollo-biz/src/test/java/com/ctrip/framework/apollo/biz/utils/ReleaseKeyGeneratorTest.java
index a36a75a2013..a074623e7f6 100644
--- a/apollo-biz/src/test/java/com/ctrip/framework/apollo/biz/utils/ReleaseKeyGeneratorTest.java
+++ b/apollo-biz/src/test/java/com/ctrip/framework/apollo/biz/utils/ReleaseKeyGeneratorTest.java
@@ -23,8 +23,6 @@
 
 import java.util.List;
 import org.junit.Test;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
@@ -33,7 +31,6 @@
 import java.util.concurrent.TimeUnit;
 
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
 
 /**
  * @author Jason Song(song_s@ctrip.com)
@@ -80,7 +77,8 @@ public void testMessageToList() {
 
     message = "appId+cluster";
     keys = ReleaseMessageKeyGenerator.messageToList(message);
-    assertNull(keys);
+    assert keys != null;
+    assertEquals(0, keys.size());
   }
 
   private Runnable generateReleaseKeysTask(Namespace namespace, Set<String> releaseKeys,