HBASE-25939 Move more tests code for StochasticLoadBalancer to hbase-balancer module (#3331)

Signed-off-by: Yulin Niu <niuyulin@apache.org>

hbase-balancer/src/main/java/org/apache/hadoop/hbase/master/balancer/LoadBalancerFactory.java

@@ -27,7 +27,10 @@ import org.apache.yetus.audience.InterfaceAudience;
  * The class that creates a load balancer from a conf.
  */
 @InterfaceAudience.Private
-public class LoadBalancerFactory {
+public final class LoadBalancerFactory {
+
+  private LoadBalancerFactory() {
+  }
 
   /**
    * The default {@link LoadBalancer} class.

hbase-balancer/src/test/java/org/apache/hadoop/hbase/master/balancer/HeterogeneousCostRulesTestHelper.java

@@ -0,0 +1,67 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hbase.master.balancer;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Path;
+import java.util.Collections;
+import java.util.List;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+final class HeterogeneousCostRulesTestHelper {
+
+  private static final Logger LOG = LoggerFactory.getLogger(HeterogeneousCostRulesTestHelper.class);
+
+  static final String DEFAULT_RULES_FILE_NAME = "hbase-balancer.rules";
+
+  private HeterogeneousCostRulesTestHelper() {
+  }
+
+  /**
+   * Create rule file with the given rules.
+   * @param file Name of file to write rules into.
+   * @return Full file name of the rules file which is <code>dir</code> + DEFAULT_RULES_FILE_NAME.
+   */
+  static String createRulesFile(String file, final List<String> rules) throws IOException {
+    cleanup(file);
+    Path path = Files.createFile(FileSystems.getDefault().getPath(file));
+    return Files.write(path, rules, StandardCharsets.UTF_8).toString();
+  }
+
+  /**
+   * Create rule file with empty rules.
+   * @param file Name of file to write rules into.
+   * @return Full file name of the rules file which is <code>dir</code> + DEFAULT_RULES_FILE_NAME.
+   */
+  static String createRulesFile(String file) throws IOException {
+    return createRulesFile(file, Collections.emptyList());
+  }
+
+  static void cleanup(String file) throws IOException {
+    try {
+      Files.delete(FileSystems.getDefault().getPath(file));
+    } catch (NoSuchFileException nsfe) {
+      LOG.warn("FileNotFoundException for {}", file, nsfe);
+    }
+  }
+}

hbase-balancer/src/test/java/org/apache/hadoop/hbase/master/balancer/LoadBalancerPerformanceEvaluation.java

@@ -87,7 +87,8 @@ public class LoadBalancerPerformanceEvaluation extends AbstractHBaseTool {
 
   // Non-default configurations.
   private void setupConf() {
-    conf.setClass(HConstants.HBASE_MASTER_LOADBALANCER_CLASS, loadBalancerClazz, LoadBalancer.class);
+    conf.setClass(HConstants.HBASE_MASTER_LOADBALANCER_CLASS, loadBalancerClazz,
+      LoadBalancer.class);
     loadBalancer = LoadBalancerFactory.getLoadBalancer(conf);
   }
 

hbase-balancer/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticLoadBalancerHeterogeneousCost.java

@@ -1,27 +1,32 @@
 /*
- * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
+ * Licensed to the Apache Software Foundation (ASF) under one
- * agreements. See the NOTICE file distributed with this work for additional information regarding
+ * or more contributor license agreements.  See the NOTICE file
- * copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * distributed with this work for additional information
- * "License"); you may not use this file except in compliance with the License. You may obtain a
+ * regarding copyright ownership.  The ASF licenses this file
- * copy of the License at
+ * to you under the Apache License, Version 2.0 (the
- * <p>
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * <p>
+ *
- * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * Unless required by applicable law or agreed to in writing, software
- * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * distributed under the License is distributed on an "AS IS" BASIS,
- * or implied. See the License for the specific language governing permissions and limitations under
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * the License.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  */
 package org.apache.hadoop.hbase.master.balancer;
 
-import static junit.framework.TestCase.assertNotNull;
+import static org.apache.hadoop.hbase.master.balancer.HeterogeneousCostRulesTestHelper.DEFAULT_RULES_FILE_NAME;
-import static junit.framework.TestCase.assertTrue;
+import static org.apache.hadoop.hbase.master.balancer.HeterogeneousCostRulesTestHelper.createRulesFile;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 
 import java.io.IOException;
+import java.util.ArrayDeque;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Queue;
@@ -30,7 +35,7 @@ import java.util.TreeMap;
 import java.util.concurrent.ThreadLocalRandom;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.hbase.HBaseClassTestRule;
-import org.apache.hadoop.hbase.HBaseTestingUtility;
+import org.apache.hadoop.hbase.HBaseCommonTestingUtility;
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.client.RegionInfo;
@@ -48,6 +53,7 @@ import org.slf4j.LoggerFactory;
 
 @Category({ MasterTests.class, MediumTests.class })
 public class TestStochasticLoadBalancerHeterogeneousCost extends StochasticBalancerTestBase {
+
   @ClassRule
   public static final HBaseClassTestRule CLASS_RULE =
     HBaseClassTestRule.forClass(TestStochasticLoadBalancerHeterogeneousCost.class);
@@ -55,7 +61,7 @@ public class TestStochasticLoadBalancerHeterogeneousCost extends StochasticBalan
   private static final Logger LOG =
     LoggerFactory.getLogger(TestStochasticLoadBalancerHeterogeneousCost.class);
   private static final double ALLOWED_WINDOW = 1.20;
-  private static final HBaseTestingUtility HTU = new HBaseTestingUtility();
+  private static final HBaseCommonTestingUtility HTU = new HBaseCommonTestingUtility();
   private static String RULES_FILE;
 
   @BeforeClass
@@ -69,10 +75,8 @@ public class TestStochasticLoadBalancerHeterogeneousCost extends StochasticBalan
       HeterogeneousRegionCountCostFunction.class.getName());
     // Need to ensure test dir has been created.
     assertTrue(FileSystem.get(HTU.getConfiguration()).mkdirs(HTU.getDataTestDir()));
-    RULES_FILE = HTU.getDataTestDir(
+    RULES_FILE = HTU.getDataTestDir(DEFAULT_RULES_FILE_NAME).toString();
-      TestStochasticLoadBalancerHeterogeneousCostRules.DEFAULT_RULES_FILE_NAME).toString();
+    conf.set(HeterogeneousRegionCountCostFunction.HBASE_MASTER_BALANCER_HETEROGENEOUS_RULES_FILE,
-    conf.set(
-      HeterogeneousRegionCountCostFunction.HBASE_MASTER_BALANCER_HETEROGENEOUS_RULES_FILE,
       RULES_FILE);
     loadBalancer = new StochasticLoadBalancer();
     loadBalancer.setClusterInfoProvider(new DummyClusterInfoProvider(conf));
@@ -146,7 +150,7 @@ public class TestStochasticLoadBalancerHeterogeneousCost extends StochasticBalan
     final int numRegions = 120;
     final int numRegionsPerServer = 60;
 
-    TestStochasticLoadBalancerHeterogeneousCostRules.createRulesFile(RULES_FILE);
+    createRulesFile(RULES_FILE);
     final Map<ServerName, List<RegionInfo>> serverMap =
       this.createServerMap(numNodes, numRegions, numRegionsPerServer, 1, 1);
     final List<RegionPlan> plans =
@@ -159,12 +163,13 @@ public class TestStochasticLoadBalancerHeterogeneousCost extends StochasticBalan
   private void testHeterogeneousWithCluster(final int numNodes, final int numRegions,
     final int numRegionsPerServer, final List<String> rules) throws IOException {
 
-    TestStochasticLoadBalancerHeterogeneousCostRules.createRulesFile(RULES_FILE, rules);
+    createRulesFile(RULES_FILE, rules);
     final Map<ServerName, List<RegionInfo>> serverMap =
       this.createServerMap(numNodes, numRegions, numRegionsPerServer, 1, 1);
     this.testWithCluster(serverMap, null, true, false);
   }
 
+  @Override
   protected void testWithCluster(final Map<ServerName, List<RegionInfo>> serverMap,
     final RackManager rackManager, final boolean assertFullyBalanced,
     final boolean assertFullyBalancedForReplicas) {
@@ -196,8 +201,7 @@ public class TestStochasticLoadBalancerHeterogeneousCost extends StochasticBalan
         final HeterogeneousRegionCountCostFunction cf =
           new HeterogeneousRegionCountCostFunction(conf);
         assertNotNull(cf);
-        BalancerClusterState cluster =
+        BalancerClusterState cluster = new BalancerClusterState(serverMap, null, null, null);
-            new BalancerClusterState(serverMap, null, null, null);
         cf.prepare(cluster);
 
         // checking that we all hosts have a number of regions below their limit
@@ -212,10 +216,9 @@ public class TestStochasticLoadBalancerHeterogeneousCost extends StochasticBalan
 
           // as the balancer is stochastic, we cannot check exactly the result of the balancing,
           // hence the allowedWindow parameter
-          assertTrue("Host " + sn.getHostname() + " should be below "
+          assertTrue("Host " + sn.getHostname() + " should be below " +
-              + cf.overallUsage * ALLOWED_WINDOW * 100 + "%; " + cf.overallUsage +
+            cf.overallUsage * ALLOWED_WINDOW * 100 + "%; " + cf.overallUsage + ", " + usage + ", " +
-              ", " + usage + ", " + numberRegions + ", " + limit,
+            numberRegions + ", " + limit, usage <= cf.overallUsage * ALLOWED_WINDOW);
-            usage <= cf.overallUsage * ALLOWED_WINDOW);
         }
       }
 
@@ -266,7 +269,7 @@ public class TestStochasticLoadBalancerHeterogeneousCost extends StochasticBalan
     return servers;
   }
 
-  private Queue<ServerName> serverQueue = new LinkedList<>();
+  private Queue<ServerName> serverQueue = new ArrayDeque<>();
 
   private ServerAndLoad createServer(final String host) {
     if (!this.serverQueue.isEmpty()) {
@@ -280,12 +283,11 @@ public class TestStochasticLoadBalancerHeterogeneousCost extends StochasticBalan
     return new ServerAndLoad(sn, 0);
   }
 
-  static class FairRandomCandidateGenerator extends
+  static class FairRandomCandidateGenerator extends RandomCandidateGenerator {
-    RandomCandidateGenerator {
 
     @Override
-    public BalanceAction pickRandomRegions(BalancerClusterState cluster,
+    public BalanceAction pickRandomRegions(BalancerClusterState cluster, int thisServer,
-      int thisServer, int otherServer) {
+      int otherServer) {
       if (thisServer < 0 || otherServer < 0) {
         return BalanceAction.NULL_ACTION;
       }

hbase-balancer/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticLoadBalancerHeterogeneousCostRules.java

@@ -1,36 +1,34 @@
 /*
- * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
+ * Licensed to the Apache Software Foundation (ASF) under one
- * agreements. See the NOTICE file distributed with this work for additional information regarding
+ * or more contributor license agreements.  See the NOTICE file
- * copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * distributed with this work for additional information
- * "License"); you may not use this file except in compliance with the License. You may obtain a
+ * regarding copyright ownership.  The ASF licenses this file
- * copy of the License at
+ * to you under the Apache License, Version 2.0 (the
- * <p>
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
  *     http://www.apache.org/licenses/LICENSE-2.0
- * <p>
+ *
- * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * Unless required by applicable law or agreed to in writing, software
- * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * distributed under the License is distributed on an "AS IS" BASIS,
- * or implied. See the License for the specific language governing permissions and limitations under
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * the License.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  */
 package org.apache.hadoop.hbase.master.balancer;
 
+import static org.apache.hadoop.hbase.master.balancer.HeterogeneousCostRulesTestHelper.DEFAULT_RULES_FILE_NAME;
+import static org.apache.hadoop.hbase.master.balancer.HeterogeneousCostRulesTestHelper.cleanup;
+import static org.apache.hadoop.hbase.master.balancer.HeterogeneousCostRulesTestHelper.createRulesFile;
+import static org.junit.Assert.assertEquals;
+
 import java.io.IOException;
-import java.nio.charset.Charset;
-import java.nio.file.FileSystems;
-import java.nio.file.NoSuchFileException;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.List;
-import org.apache.hadoop.conf.Configuration;
-import org.apache.hadoop.fs.FSDataOutputStream;
-import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hbase.HBaseClassTestRule;
-import org.apache.hadoop.hbase.HBaseTestingUtility;
+import org.apache.hadoop.hbase.HBaseCommonTestingUtility;
 import org.apache.hadoop.hbase.testclassification.MasterTests;
 import org.apache.hadoop.hbase.testclassification.MediumTests;
-import org.apache.hadoop.hdfs.DistributedFileSystem;
-import org.apache.hadoop.hdfs.MiniDFSCluster;
-import org.junit.Assert;
 import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.ClassRule;
@@ -41,15 +39,15 @@ import org.junit.rules.TestName;
 
 @Category({ MasterTests.class, MediumTests.class })
 public class TestStochasticLoadBalancerHeterogeneousCostRules extends StochasticBalancerTestBase {
+
   @ClassRule
   public static final HBaseClassTestRule CLASS_RULE =
       HBaseClassTestRule.forClass(TestStochasticLoadBalancerHeterogeneousCostRules.class);
   @Rule
   public TestName name = new TestName();
 
-  static final String DEFAULT_RULES_FILE_NAME = "hbase-balancer.rules";
   private HeterogeneousRegionCountCostFunction costFunction;
-  private static final HBaseTestingUtility HTU = new HBaseTestingUtility();
+  private static final HBaseCommonTestingUtility HTU = new HBaseCommonTestingUtility();
 
   /**
    * Make a file for rules that is inside a temporary test dir named for the method so it doesn't
@@ -60,47 +58,22 @@ public class TestStochasticLoadBalancerHeterogeneousCostRules extends Stochastic
   @BeforeClass
   public static void beforeClass() throws IOException {
     // Ensure test dir is created
-    HTU.getTestFileSystem().mkdirs(HTU.getDataTestDir());
+    HTU.getDataTestDir().getFileSystem(HTU.getConfiguration()).mkdirs(HTU.getDataTestDir());
   }
 
   @Before
   public void before() throws IOException {
     // New rules file name per test.
-    this.rulesFilename = HTU.getDataTestDir(
+    this.rulesFilename = HTU
-      this.name.getMethodName() + "." + DEFAULT_RULES_FILE_NAME).toString();
+      .getDataTestDir(
+        this.name.getMethodName() + "." + DEFAULT_RULES_FILE_NAME)
+      .toString();
     // Set the created rules filename into the configuration.
     HTU.getConfiguration().set(
       HeterogeneousRegionCountCostFunction.HBASE_MASTER_BALANCER_HETEROGENEOUS_RULES_FILE,
       this.rulesFilename);
   }
 
-  /**
-   * @param file Name of file to write rules into.
-   * @return Full file name of the rules file which is <code>dir</code> + DEFAULT_RULES_FILE_NAME.
-   */
-  static String createRulesFile(String file, final List<String> lines) throws IOException {
-    cleanup(file);
-    java.nio.file.Path path =
-      java.nio.file.Files.createFile(FileSystems.getDefault().getPath(file));
-    return java.nio.file.Files.write(path, lines, Charset.forName("UTF-8")).toString();
-  }
-
-  /**
-   * @param file Name of file to write rules into.
-   * @return Full file name of the rules file which is <code>dir</code> + DEFAULT_RULES_FILE_NAME.
-   */
-  static String createRulesFile(String file) throws IOException {
-    return createRulesFile(file, Collections.emptyList());
-  }
-
-  private static void cleanup(String file) throws IOException {
-    try {
-      java.nio.file.Files.delete(FileSystems.getDefault().getPath(file));
-    } catch (NoSuchFileException nsfe) {
-      System.out.println("FileNotFoundException for " + file);
-    }
-  }
-
   @Test
   public void testNoRules() throws IOException {
     // Override what is in the configuration with the name of a non-existent file!
@@ -109,7 +82,7 @@ public class TestStochasticLoadBalancerHeterogeneousCostRules extends Stochastic
       "non-existent-file!");
     this.costFunction = new HeterogeneousRegionCountCostFunction(HTU.getConfiguration());
     this.costFunction.loadRules();
-    Assert.assertEquals(0, this.costFunction.getNumberOfRulesLoaded());
+    assertEquals(0, this.costFunction.getNumberOfRulesLoaded());
   }
 
   @Test
@@ -119,18 +92,18 @@ public class TestStochasticLoadBalancerHeterogeneousCostRules extends Stochastic
     // in the configuration.
     this.costFunction = new HeterogeneousRegionCountCostFunction(HTU.getConfiguration());
     this.costFunction.loadRules();
-    Assert.assertEquals(0, this.costFunction.getNumberOfRulesLoaded());
+    assertEquals(0, this.costFunction.getNumberOfRulesLoaded());
 
     createRulesFile(this.rulesFilename, Collections.singletonList("bad rules format"));
     this.costFunction = new HeterogeneousRegionCountCostFunction(HTU.getConfiguration());
     this.costFunction.loadRules();
-    Assert.assertEquals(0, this.costFunction.getNumberOfRulesLoaded());
+    assertEquals(0, this.costFunction.getNumberOfRulesLoaded());
 
     createRulesFile(this.rulesFilename, Arrays.asList("srv[1-2] 10",
       "bad_rules format", "a"));
     this.costFunction = new HeterogeneousRegionCountCostFunction(HTU.getConfiguration());
     this.costFunction.loadRules();
-    Assert.assertEquals(1, this.costFunction.getNumberOfRulesLoaded());
+    assertEquals(1, this.costFunction.getNumberOfRulesLoaded());
   }
 
   @Test
@@ -144,7 +117,7 @@ public class TestStochasticLoadBalancerHeterogeneousCostRules extends Stochastic
     createRulesFile(this.rulesFilename, Arrays.asList("^server1$ 10", "^server2 21"));
     this.costFunction = new HeterogeneousRegionCountCostFunction(HTU.getConfiguration());
     this.costFunction.loadRules();
-    Assert.assertEquals(2, this.costFunction.getNumberOfRulesLoaded());
+    assertEquals(2, this.costFunction.getNumberOfRulesLoaded());
   }
 
   @Test
@@ -158,7 +131,7 @@ public class TestStochasticLoadBalancerHeterogeneousCostRules extends Stochastic
     createRulesFile(this.rulesFilename, Collections.singletonList("server[ 1"));
     this.costFunction = new HeterogeneousRegionCountCostFunction(HTU.getConfiguration());
     this.costFunction.loadRules();
-    Assert.assertEquals(0, this.costFunction.getNumberOfRulesLoaded());
+    assertEquals(0, this.costFunction.getNumberOfRulesLoaded());
   }
 
   @Test
@@ -169,38 +142,11 @@ public class TestStochasticLoadBalancerHeterogeneousCostRules extends Stochastic
     createRulesFile(this.rulesFilename, Arrays.asList("^server1$ 10", "^server2 21"));
     this.costFunction = new HeterogeneousRegionCountCostFunction(HTU.getConfiguration());
     this.costFunction.loadRules();
-    Assert.assertEquals(2, this.costFunction.getNumberOfRulesLoaded());
+    assertEquals(2, this.costFunction.getNumberOfRulesLoaded());
 
     // loading malformed configuration does not overload current
     cleanup(this.rulesFilename);
     this.costFunction.loadRules();
-    Assert.assertEquals(2, this.costFunction.getNumberOfRulesLoaded());
+    assertEquals(2, this.costFunction.getNumberOfRulesLoaded());
-  }
-
-  @Test
-  public void testLoadingFomHDFS() throws Exception {
-    HTU.startMiniDFSCluster(3);
-    try {
-      MiniDFSCluster cluster = HTU.getDFSCluster();
-      DistributedFileSystem fs = cluster.getFileSystem();
-      // Writing file
-      Path path = new Path(fs.getHomeDirectory(), DEFAULT_RULES_FILE_NAME);
-      FSDataOutputStream stream = fs.create(path);
-      stream.write("server1 10".getBytes());
-      stream.flush();
-      stream.close();
-
-      Configuration configuration = HTU.getConfiguration();
-
-      // start costFunction
-      configuration.set(
-        HeterogeneousRegionCountCostFunction.HBASE_MASTER_BALANCER_HETEROGENEOUS_RULES_FILE,
-        path.toString());
-      this.costFunction = new HeterogeneousRegionCountCostFunction(configuration);
-      this.costFunction.loadRules();
-      Assert.assertEquals(1, this.costFunction.getNumberOfRulesLoaded());
-    } finally {
-      HTU.shutdownMiniCluster();
-    }
   }
 }

hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticLoadBalancerHeterogeneousCostRulesLoadFromHDFS.java

@@ -0,0 +1,81 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hbase.master.balancer;
+
+import static org.apache.hadoop.hbase.master.balancer.HeterogeneousCostRulesTestHelper.DEFAULT_RULES_FILE_NAME;
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FSDataOutputStream;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hbase.HBaseClassTestRule;
+import org.apache.hadoop.hbase.HBaseTestingUtility;
+import org.apache.hadoop.hbase.testclassification.MasterTests;
+import org.apache.hadoop.hbase.testclassification.MediumTests;
+import org.apache.hadoop.hdfs.DistributedFileSystem;
+import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+@Category({ MasterTests.class, MediumTests.class })
+public class TestStochasticLoadBalancerHeterogeneousCostRulesLoadFromHDFS
+  extends StochasticBalancerTestBase {
+
+  @ClassRule
+  public static final HBaseClassTestRule CLASS_RULE =
+    HBaseClassTestRule.forClass(TestStochasticLoadBalancerHeterogeneousCostRulesLoadFromHDFS.class);
+
+  private HeterogeneousRegionCountCostFunction costFunction;
+  private static final HBaseTestingUtility HTU = new HBaseTestingUtility();
+
+  @Before
+  public void setUp() throws Exception {
+    HTU.startMiniCluster(1);
+  }
+
+  @After
+  public void tearDown() throws IOException {
+    HTU.shutdownMiniCluster();
+  }
+
+  @Test
+  public void testLoadingFomHDFS() throws Exception {
+    MiniDFSCluster cluster = HTU.getDFSCluster();
+    DistributedFileSystem fs = cluster.getFileSystem();
+    // Writing file
+    Path path = new Path(fs.getHomeDirectory(), DEFAULT_RULES_FILE_NAME);
+    FSDataOutputStream stream = fs.create(path);
+    stream.write("server1 10".getBytes());
+    stream.flush();
+    stream.close();
+
+    Configuration configuration = HTU.getConfiguration();
+
+    // start costFunction
+    configuration.set(
+      HeterogeneousRegionCountCostFunction.HBASE_MASTER_BALANCER_HETEROGENEOUS_RULES_FILE,
+      path.toString());
+    this.costFunction = new HeterogeneousRegionCountCostFunction(configuration);
+    this.costFunction.loadRules();
+    assertEquals(1, this.costFunction.getNumberOfRulesLoaded());
+  }
+}