RATIS-2081. Enable checkstyle for test source directory

pom.xml

@@ -787,6 +787,7 @@
         <version>${maven-checkstyle-plugin.version}</version>
         <configuration>
           <configLocation>dev-support/checkstyle.xml</configLocation>
+          <includeTestSourceDirectory>true</includeTestSourceDirectory>
           <failOnViolation>true</failOnViolation>
           <linkXRef>false</linkXRef>
         </configuration>

ratis-common/src/test/java/org/apache/ratis/BaseTest.java

@@ -52,6 +52,7 @@
 
 @Timeout(value = 100)
 public abstract class BaseTest {
+  @SuppressWarnings({"VisibilityModifier", "MemberName"})
   public final Logger LOG = LoggerFactory.getLogger(getClass());
 
   public static final TimeDuration HUNDRED_MILLIS = TimeDuration.valueOf(100, TimeUnit.MILLISECONDS);
@@ -124,7 +125,7 @@ public int getGlobalTimeoutSeconds() {
     return 100;
   }
 
-  private static final Supplier<File> rootTestDir = JavaUtils.memoize(
+  private static final Supplier<File> ROOT_TEST_DIR = JavaUtils.memoize(
       () -> JavaUtils.callAsUnchecked(() -> {
         final File dir = new File(System.getProperty("test.build.data", "target/test/data"),
             Integer.toHexString(ThreadLocalRandom.current().nextInt()));
@@ -138,7 +139,7 @@ public int getGlobalTimeoutSeconds() {
 
 
   public static File getRootTestDir() {
-    return rootTestDir.get();
+    return ROOT_TEST_DIR.get();
   }
 
   public File getClassTestDir() {

ratis-common/src/test/java/org/apache/ratis/util/TestRefCountingMap.java

@@ -26,7 +26,6 @@
 import java.util.Set;
 
 import org.apache.ratis.thirdparty.com.google.common.collect.Lists;
-import org.apache.ratis.util.RefCountingMap;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 

ratis-examples/src/test/java/org/apache/ratis/examples/ParameterizedBaseTest.java

@@ -29,8 +29,6 @@
 import org.apache.ratis.util.JavaUtils;
 import org.apache.ratis.util.TimeDuration;
 import org.junit.jupiter.api.AfterAll;
-import org.junit.jupiter.api.Test;
-import org.junit.jupiter.params.ParameterizedTest;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -47,12 +45,14 @@ public static Collection<Object[]> data() {
     return Collections.emptyList();
   }
 
-  /** For {@link ParameterizedTest} so that a cluster can be shared by multiple {@link Test} */
-  private static final AtomicReference<MiniRaftCluster> currentCluster = new AtomicReference<>();
+  /** For {@link org.junit.jupiter.params.ParameterizedTest} so that a cluster can be shared
+   * by multiple {@link org.junit.jupiter.api.Test}
+   */
+  private static final AtomicReference<MiniRaftCluster> CURRENT_CLUSTER = new AtomicReference<>();
 
-  /** Set {@link #currentCluster} to the given cluster and start it if {@link #currentCluster} is changed. */
+  /** Set {@link #CURRENT_CLUSTER} to the given cluster and start it if {@link #CURRENT_CLUSTER} is changed. */
   public static void setAndStart(MiniRaftCluster cluster) throws InterruptedException, IOException {
-    final MiniRaftCluster previous = currentCluster.getAndSet(cluster);
+    final MiniRaftCluster previous = CURRENT_CLUSTER.getAndSet(cluster);
     if (previous != cluster) {
       if (previous != null) {
         previous.shutdown();
@@ -65,7 +65,7 @@ public static void setAndStart(MiniRaftCluster cluster) throws InterruptedExcept
 
   @AfterAll
   public static void shutdownCurrentCluster() {
-    final MiniRaftCluster cluster = currentCluster.getAndSet(null);
+    final MiniRaftCluster cluster = CURRENT_CLUSTER.getAndSet(null);
     if (cluster != null) {
       cluster.shutdown();
     }

ratis-examples/src/test/java/org/apache/ratis/examples/arithmetic/TestArithmetic.java

@@ -39,6 +39,7 @@
 import static org.apache.ratis.examples.arithmetic.expression.UnaryExpression.Op.SQRT;
 import static org.apache.ratis.examples.arithmetic.expression.UnaryExpression.Op.SQUARE;
 
+@SuppressWarnings({"LocalFinalVariableName", "LocalVariableName"})
 public class TestArithmetic extends ParameterizedBaseTest {
   {
     Slf4jUtils.setLogLevel(ArithmeticStateMachine.LOG, Level.DEBUG);
@@ -107,7 +108,8 @@ void runGaussLegendre(RaftClient client) throws IOException {
       final Variable p0 = new Variable("p" + i_1);
       final Variable a1 = defineVariable(client, "a"+i, DIV.apply(ADD.apply(a0, b0), 2));
       final Variable b1 = defineVariable(client, "b"+i, SQRT.apply(MULT.apply(a0, b0)));
-      final Variable t1 = defineVariable(client, "t"+i, SUBTRACT.apply(t0, MULT.apply(p0, SQUARE.apply(SUBTRACT.apply(a0, a1)))));
+      final Variable t1 = defineVariable(client, "t"+i,
+          SUBTRACT.apply(t0, MULT.apply(p0, SQUARE.apply(SUBTRACT.apply(a0, a1)))));
       final Variable p1 = defineVariable(client, "p"+i, MULT.apply(2, p0));
 
       final Variable pi_i = new Variable("pi_"+i);

ratis-examples/src/test/java/org/apache/ratis/examples/arithmetic/TestArithmeticLogDump.java

@@ -47,17 +47,17 @@ public class TestArithmeticLogDump extends BaseTest {
 
   public static final int NUM_SERVERS = 1;
 
-  protected static final RaftProperties properties = new RaftProperties();
+  protected static final RaftProperties PROPERTIES = new RaftProperties();
 
   private final MiniRaftClusterWithSimulatedRpc cluster = MiniRaftClusterWithSimulatedRpc
       .FACTORY.newCluster(NUM_SERVERS, getProperties());
 
   public RaftProperties getProperties() {
     RaftServerConfigKeys.Rpc
-        .setSlownessTimeout(properties, TimeDuration.valueOf(1, TimeUnit.SECONDS));
-    properties.setClass(MiniRaftCluster.STATEMACHINE_CLASS_KEY,
+        .setSlownessTimeout(PROPERTIES, TimeDuration.valueOf(1, TimeUnit.SECONDS));
+    PROPERTIES.setClass(MiniRaftCluster.STATEMACHINE_CLASS_KEY,
         SimpleStateMachine4Testing.class, StateMachine.class);
-    return properties;
+    return PROPERTIES;
   }
 
   @BeforeEach

ratis-examples/src/test/java/org/apache/ratis/examples/arithmetic/expression/TestExpression.java

@@ -25,6 +25,7 @@
 import java.util.Random;
 import java.util.concurrent.ThreadLocalRandom;
 
+@SuppressWarnings("AvoidNestedBlocks")
 public class TestExpression extends BaseTest {
   @Override
   public int getGlobalTimeoutSeconds() {

ratis-examples/src/test/java/org/apache/ratis/examples/common/TestSubCommand.java

@@ -21,12 +21,9 @@
 
 import java.util.Collection;
 import java.util.Collections;
-import org.junit.Test;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
-import org.junit.runner.RunWith;
-import org.junit.runners.Parameterized;
 
 public class TestSubCommand {
 

ratis-examples/src/test/java/org/apache/ratis/examples/filestore/FileStoreWriter.java

@@ -44,17 +44,17 @@
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicInteger;
 
-class FileStoreWriter implements Closeable {
+final class FileStoreWriter implements Closeable {
   public static final Logger LOG = LoggerFactory.getLogger(FileStoreWriter.class);
 
-  final long seed = ThreadLocalRandom.current().nextLong();
-  final byte[] buffer = new byte[4 << 10];
+  private final long seed = ThreadLocalRandom.current().nextLong();
+  private final byte[] buffer = new byte[4 << 10];
 
-  final String fileName;
-  final SizeInBytes fileSize;
-  final FileStoreClient client;
-  final Executor asyncExecutor;
-  final int bufferSize;
+  private final String fileName;
+  private final SizeInBytes fileSize;
+  private final FileStoreClient client;
+  private final Executor asyncExecutor;
+  private final int bufferSize;
 
   static Builder newBuilder() {
     return new Builder();

ratis-examples/src/test/java/org/apache/ratis/examples/filestore/TestFileStoreStreamingWithGrpcCluster.java

@@ -19,7 +19,8 @@
 
 import org.apache.ratis.datastream.MiniRaftClusterWithRpcTypeGrpcAndDataStreamTypeNetty;
 
-public class TestFileStoreStreamingWithGrpcCluster extends FileStoreStreamingBaseTest<MiniRaftClusterWithRpcTypeGrpcAndDataStreamTypeNetty>
+public class TestFileStoreStreamingWithGrpcCluster extends
+    FileStoreStreamingBaseTest<MiniRaftClusterWithRpcTypeGrpcAndDataStreamTypeNetty>
     implements MiniRaftClusterWithRpcTypeGrpcAndDataStreamTypeNetty.FactoryGet {
 
 }

ratis-examples/src/test/java/org/apache/ratis/server/impl/TestReadAfterWrite.java

@@ -44,6 +44,7 @@
 
 import static org.apache.ratis.examples.arithmetic.expression.BinaryExpression.Op.ADD;
 
+@SuppressWarnings("LocalFinalVariableName")
 public class TestReadAfterWrite
     extends BaseTest
     implements MiniRaftClusterWithGrpc.FactoryGet {

ratis-grpc/src/test/java/org/apache/ratis/grpc/MiniRaftClusterWithGrpc.java

@@ -61,7 +61,7 @@ default Factory<MiniRaftClusterWithGrpc> getFactory() {
     }
   }
 
-  public static final DelayLocalExecutionInjection sendServerRequestInjection =
+  public static final DelayLocalExecutionInjection SEND_SERVER_REQUEST_INJECTION =
       new DelayLocalExecutionInjection(GrpcService.GRPC_SEND_SERVER_REQUEST);
 
   protected MiniRaftClusterWithGrpc(String[] ids, String[] listenerIds, RaftProperties properties,
@@ -82,7 +82,7 @@ protected Parameters setPropertiesAndInitParameters(RaftPeerId id, RaftGroup gro
   @Override
   protected void blockQueueAndSetDelay(String leaderId, int delayMs)
       throws InterruptedException {
-    RaftTestUtil.blockQueueAndSetDelay(getServers(), sendServerRequestInjection,
+    RaftTestUtil.blockQueueAndSetDelay(getServers(), SEND_SERVER_REQUEST_INJECTION,
         leaderId, delayMs, getTimeoutMax());
   }
 

ratis-metrics-default/src/test/java/org/apache/ratis/metrics/TestMetricRegistriesLoader.java

@@ -67,7 +67,7 @@ public void testAddRemoveReporter() {
     Consumer<RatisMetricRegistry> reporter = v-> cntr.incrementAndGet();
     Consumer<RatisMetricRegistry> stopReporter = v-> cntr.incrementAndGet();
     r.addReporterRegistration(reporter, stopReporter);
-    
+
     // check if add and remove of metric do reporting counter increase
     MetricRegistryInfo info = new MetricRegistryInfo("t1", "t1", "t1", "t1");
     r.create(info);

ratis-netty/src/test/java/org/apache/ratis/netty/MiniRaftClusterWithNetty.java

@@ -48,7 +48,7 @@ default Factory<MiniRaftClusterWithNetty> getFactory() {
     }
   }
 
-  public static final DelayLocalExecutionInjection sendServerRequest
+  public static final DelayLocalExecutionInjection SEND_SERVER_REQUEST
       = new DelayLocalExecutionInjection(NettyRpcService.SEND_SERVER_REQUEST);
 
   protected MiniRaftClusterWithNetty(String[] ids, String[] listenerIds, RaftProperties properties) {
@@ -64,7 +64,7 @@ protected Parameters setPropertiesAndInitParameters(RaftPeerId id, RaftGroup gro
   @Override
   protected void blockQueueAndSetDelay(String leaderId, int delayMs)
       throws InterruptedException {
-    RaftTestUtil.blockQueueAndSetDelay(getServers(), sendServerRequest,
+    RaftTestUtil.blockQueueAndSetDelay(getServers(), SEND_SERVER_REQUEST,
         leaderId, delayMs, getTimeoutMax());
   }
 }

ratis-server/src/test/java/org/apache/ratis/InstallSnapshotFromLeaderTests.java

@@ -129,12 +129,13 @@ private void testMultiFileInstallSnapshot(CLUSTER cluster) throws Exception {
 
   private static class StateMachineWithMultiNestedSnapshotFile extends SimpleStateMachine4Testing {
 
-    File snapshotRoot;
-    File file1;
-    File file2;
+    private File snapshotRoot;
+    private File file1;
+    private File file2;
 
     @Override
-    public synchronized void initialize(RaftServer server, RaftGroupId groupId, RaftStorage raftStorage) throws IOException {
+    public synchronized void initialize(RaftServer server, RaftGroupId groupId, RaftStorage raftStorage)
+        throws IOException {
       super.initialize(server, groupId, raftStorage);
 
             // contains two snapshot files
@@ -215,7 +216,8 @@ private static class StateMachineWithSeparatedSnapshotPath extends SimpleStateMa
     private File tmpDir;
 
     @Override
-    public synchronized void initialize(RaftServer server, RaftGroupId groupId, RaftStorage raftStorage) throws IOException {
+    public synchronized void initialize(RaftServer server, RaftGroupId groupId, RaftStorage raftStorage)
+        throws IOException {
       super.initialize(server, groupId, raftStorage);
       this.root = new File("/tmp/ratis-tests/statemachine/" + getId().toString());
       this.snapshotDir = new File(root, "snapshot");
@@ -238,7 +240,8 @@ public synchronized void pause() {
     public long takeSnapshot() {
       final TermIndex lastApplied = getLastAppliedTermIndex();
       final File snapshotTmpDir = new File(tmpDir, UUID.randomUUID().toString());
-      final File snapshotRealDir = new File(snapshotDir, String.format("%d_%d", lastApplied.getTerm(), lastApplied.getIndex()));
+      final File snapshotRealDir = new File(snapshotDir,
+          String.format("%d_%d", lastApplied.getTerm(), lastApplied.getIndex()));
 
       try {
         FileUtils.deleteFully(snapshotRealDir);