diff --git a/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestBaseLoadBalancer.java b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestBaseLoadBalancer.java
index 3be5bbe7b34..bed132190a5 100644
--- a/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestBaseLoadBalancer.java
+++ b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestBaseLoadBalancer.java
@@ -47,6 +47,8 @@ import org.apache.hadoop.hbase.master.RackManager;
 import org.apache.hadoop.hbase.master.RegionPlan;
 import org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster;
 import org.apache.hadoop.hbase.master.balancer.BaseLoadBalancer.Cluster.MoveRegionAction;
+import org.apache.hadoop.net.DNSToSwitchMapping;
+import org.apache.hadoop.net.ScriptBasedMapping;
 import org.junit.BeforeClass;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
@@ -71,9 +73,26 @@ public class TestBaseLoadBalancer extends BalancerTestBase {
       new int[] { 1, 3 }, new int[] { 2, 3 }, new int[] { 3, 3 }, new int[] { 25, 3 },
       new int[] { 2, 10 }, new int[] { 2, 100 }, new int[] { 12, 10 }, new int[] { 12, 100 }, };
 
+  // This class is introduced because IP to rack resolution can be lengthy.
+  public static class MockMapping extends ScriptBasedMapping {
+    public MockMapping(Configuration conf) {
+    }
+
+    private static String RACK = "rack";
+    @Override
+    public List<String> resolve(List<String> names) {
+      List<String> ret = new ArrayList<String>(names.size());
+      for (String name : names) {
+        ret.add(RACK);
+      }
+      return ret;
+    }
+  }
+
   @BeforeClass
   public static void beforeAllTests() throws Exception {
     Configuration conf = HBaseConfiguration.create();
+    conf.setClass("hbase.util.ip.to.rack.determiner", MockMapping.class, DNSToSwitchMapping.class);
     loadBalancer = new MockBalancer();
     loadBalancer.setConf(conf);
     MasterServices st = Mockito.mock(MasterServices.class);