HADOOP-14310. RolloverSignerSecretProvider.LOG should be @VisibleForTesting

(Contributed by Arun Shanmugam Kumar via Daniel Templeton)

hadoop-common-project/hadoop-auth/pom.xml

@@ -181,6 +181,11 @@
       <version>${apacheds.version}</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava</artifactId>
+      <scope>compile</scope>
+    </dependency>
   </dependencies>
 
   <build>

hadoop-common-project/hadoop-auth/src/main/java/org/apache/hadoop/security/authentication/util/RolloverSignerSecretProvider.java

@@ -18,6 +18,7 @@ import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
 import javax.servlet.ServletContext;
+import com.google.common.annotations.VisibleForTesting;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.slf4j.Logger;
@@ -38,6 +39,7 @@ import org.slf4j.LoggerFactory;
 public abstract class RolloverSignerSecretProvider
     extends SignerSecretProvider {
 
+  @VisibleForTesting
   static Logger LOG = LoggerFactory.getLogger(
     RolloverSignerSecretProvider.class);
   /**