diff --git a/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java b/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
index 75b1f2e..917238b 100644
--- a/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
+++ b/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
@@ -15,9 +15,11 @@
 package com.google.gerrit.elasticsearch;
 
 import static com.google.common.base.Preconditions.checkState;
+import static org.apache.commons.codec.binary.Base64.decodeBase64;
 import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
 
 import com.google.common.base.Strings;
+import com.google.common.collect.FluentIterable;
 import com.google.common.collect.Iterables;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.SitePaths;
@@ -26,6 +28,9 @@
 import com.google.gerrit.server.index.IndexUtils;
 import com.google.gerrit.server.index.Schema;
 import com.google.gerrit.server.index.Schema.Values;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonObject;
+import com.google.gwtorm.protobuf.ProtobufCodec;
 
 import org.eclipse.jgit.lib.Config;
 import org.elasticsearch.common.xcontent.XContentBuilder;
@@ -33,6 +38,7 @@
 import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.util.List;
 import java.util.concurrent.TimeUnit;
 
 import io.searchbox.client.JestClientFactory;
@@ -46,6 +52,16 @@
 import io.searchbox.indices.IndicesExists;
 
 abstract class AbstractElasticIndex<K, V> implements Index<K, V> {
+  protected static <T> List<T> decodeProtos(JsonObject doc, String fieldName,
+      ProtobufCodec<T> codec) {
+    JsonArray field = doc.getAsJsonArray(fieldName);
+    if (field == null) {
+      return null;
+    }
+    return FluentIterable.from(field)
+        .transform(i -> codec.decode(decodeBase64(i.toString())))
+        .toList();
+  }
 
   private final Schema<V> schema;
   private final FillArgs fillArgs;
@@ -55,7 +71,6 @@
   protected final String indexName;
   protected final JestHttpClient client;
 
-
   AbstractElasticIndex(@GerritServerConfig Config cfg,
       FillArgs fillArgs,
       SitePaths sitePaths,
diff --git a/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java b/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java
index 762b868..a4c74ed 100644
--- a/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java
+++ b/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java
@@ -34,9 +34,7 @@
 import com.google.gerrit.server.ReviewerSet;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.SitePaths;
-import com.google.gerrit.server.index.FieldDef;
 import com.google.gerrit.server.index.FieldDef.FillArgs;
-import com.google.gerrit.server.index.FieldType;
 import com.google.gerrit.server.index.IndexUtils;
 import com.google.gerrit.server.index.QueryOptions;
 import com.google.gerrit.server.index.Schema;
@@ -56,7 +54,6 @@
 import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
-import com.google.gwtorm.protobuf.ProtobufCodec;
 import com.google.gwtorm.server.OrmException;
 import com.google.gwtorm.server.ResultSet;
 import com.google.inject.Provider;
@@ -94,30 +91,9 @@
     MappingProperties closedChanges;
 
     ChangeMapping(Schema<ChangeData> schema) {
-      ElasticMapping.Builder mappingBuilder = new ElasticMapping.Builder();
-      for (FieldDef<?, ?> field : schema.getFields().values()) {
-        String name = field.getName();
-        FieldType<?> fieldType = field.getType();
-        if (fieldType == FieldType.EXACT) {
-          mappingBuilder.addExactField(name);
-        } else if (fieldType == FieldType.TIMESTAMP) {
-          mappingBuilder.addTimestamp(name);
-        } else if (fieldType == FieldType.INTEGER
-            || fieldType == FieldType.INTEGER_RANGE
-            || fieldType == FieldType.LONG) {
-          mappingBuilder.addNumber(name);
-        } else if (fieldType == FieldType.PREFIX
-            || fieldType == FieldType.FULL_TEXT
-            || fieldType == FieldType.STORED_ONLY) {
-          mappingBuilder.addString(name);
-        } else {
-          throw new IllegalArgumentException(
-              "Unsupported field type " + fieldType.getName());
-        }
-      }
-      MappingProperties mapping = mappingBuilder.build();
-      openChanges = mapping;
-      closedChanges = mapping;
+      MappingProperties mapping = ElasticMapping.createMapping(schema);
+      this.openChanges = mapping;
+      this.closedChanges = mapping;
     }
   }
 
@@ -149,17 +125,6 @@
         .setFieldNamingPolicy(LOWER_CASE_WITH_UNDERSCORES).create();
   }
 
-  private static <T> List<T> decodeProtos(JsonObject doc, String fieldName,
-      ProtobufCodec<T> codec) {
-    JsonArray field = doc.getAsJsonArray(fieldName);
-    if (field == null) {
-      return null;
-    }
-    return FluentIterable.from(field)
-        .transform(i -> codec.decode(decodeBase64(i.toString())))
-        .toList();
-  }
-
   @Override
   public void replace(ChangeData cd) throws IOException {
     String deleteIndex;
@@ -236,7 +201,7 @@
         sort.setIgnoreUnmapped();
       }
       QueryBuilder qb = queryBuilder.toQueryBuilder(p);
-      fields = IndexUtils.fields(opts);
+      fields = IndexUtils.changeFields(opts);
       SearchSourceBuilder searchSource = new SearchSourceBuilder()
           .query(qb)
           .from(opts.start())
diff --git a/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticMapping.java b/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticMapping.java
index e3f7e96..45f686f 100644
--- a/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticMapping.java
+++ b/gerrit-elasticsearch/src/main/java/com/google/gerrit/elasticsearch/ElasticMapping.java
@@ -15,10 +15,38 @@
 package com.google.gerrit.elasticsearch;
 
 import com.google.common.collect.ImmutableMap;
+import com.google.gerrit.server.index.FieldDef;
+import com.google.gerrit.server.index.FieldType;
+import com.google.gerrit.server.index.Schema;
 
 import java.util.Map;
 
 class ElasticMapping {
+  static MappingProperties createMapping(Schema<?> schema) {
+    ElasticMapping.Builder mapping = new ElasticMapping.Builder();
+    for (FieldDef<?, ?> field : schema.getFields().values()) {
+      String name = field.getName();
+      FieldType<?> fieldType = field.getType();
+      if (fieldType == FieldType.EXACT) {
+        mapping.addExactField(name);
+      } else if (fieldType == FieldType.TIMESTAMP) {
+        mapping.addTimestamp(name);
+      } else if (fieldType == FieldType.INTEGER
+          || fieldType == FieldType.INTEGER_RANGE
+          || fieldType == FieldType.LONG) {
+        mapping.addNumber(name);
+      } else if (fieldType == FieldType.PREFIX
+          || fieldType == FieldType.FULL_TEXT
+          || fieldType == FieldType.STORED_ONLY) {
+        mapping.addString(name);
+      } else {
+        throw new IllegalStateException(
+            "Unsupported field type: " + fieldType.getName());
+      }
+    }
+    return mapping.build();
+  }
+
   static class Builder {
     private final ImmutableMap.Builder<String, FieldProperties> fields =
         new ImmutableMap.Builder<>();
diff --git a/gerrit-elasticsearch/src/test/java/com/google/gerrit/elasticsearch/ElasticQueryChangesTest.java b/gerrit-elasticsearch/src/test/java/com/google/gerrit/elasticsearch/ElasticQueryChangesTest.java
index 9a6755f..4b76e4b 100644
--- a/gerrit-elasticsearch/src/test/java/com/google/gerrit/elasticsearch/ElasticQueryChangesTest.java
+++ b/gerrit-elasticsearch/src/test/java/com/google/gerrit/elasticsearch/ElasticQueryChangesTest.java
@@ -14,123 +14,60 @@
 
 package com.google.gerrit.elasticsearch;
 
-import static com.google.common.base.Preconditions.checkState;
-import static com.google.common.truth.Truth.assertThat;
 import static com.google.gerrit.elasticsearch.ElasticChangeIndex.CHANGES_PREFIX;
 import static com.google.gerrit.elasticsearch.ElasticChangeIndex.CLOSED_CHANGES;
 import static com.google.gerrit.elasticsearch.ElasticChangeIndex.OPEN_CHANGES;
 
-import com.google.common.base.Strings;
-import com.google.common.io.Files;
 import com.google.gerrit.elasticsearch.ElasticChangeIndex.ChangeMapping;
-import com.google.gerrit.server.index.IndexModule.IndexType;
+import com.google.gerrit.elasticsearch.ElasticTestUtils.ElasticNodeInfo;
 import com.google.gerrit.server.index.change.ChangeSchemaDefinitions;
 import com.google.gerrit.server.query.change.AbstractQueryChangesTest;
 import com.google.gerrit.testutil.InMemoryModule;
 import com.google.gerrit.testutil.InMemoryRepositoryManager.Repo;
-import com.google.gson.FieldNamingPolicy;
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
 import com.google.inject.Guice;
 import com.google.inject.Injector;
 
 import org.eclipse.jgit.junit.TestRepository;
 import org.eclipse.jgit.lib.Config;
-import org.elasticsearch.action.admin.cluster.node.info.NodesInfoRequest;
-import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.node.Node;
-import org.elasticsearch.node.NodeBuilder;
 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Test;
 
-import java.io.File;
-import java.nio.file.Path;
-import java.util.Iterator;
-import java.util.Map;
 import java.util.concurrent.ExecutionException;
 
 public class ElasticQueryChangesTest extends AbstractQueryChangesTest {
-  private static final Gson gson = new GsonBuilder()
-      .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
-      .create();
   private static final String INDEX_NAME =
       String.format("%s%04d", CHANGES_PREFIX,
           ChangeSchemaDefinitions.INSTANCE.getLatest().getVersion());
-  private static Node node;
-  private static String port;
-  private static File elasticDir;
-
-  static class NodeInfo {
-    String httpAddress;
-  }
-
-  static class Info {
-    Map<String, NodeInfo> nodes;
-  }
+  private static ElasticNodeInfo nodeInfo;
 
   @BeforeClass
   public static void startIndexService()
       throws InterruptedException, ExecutionException {
-    if (node != null) {
+    if (nodeInfo != null) {
       // do not start Elasticsearch twice
       return;
     }
-    elasticDir = Files.createTempDir();
-    Path elasticDirPath = elasticDir.toPath();
-    Settings settings = Settings.settingsBuilder()
-        .put("cluster.name", "gerrit")
-        .put("node.name", "Gerrit Elasticsearch Test Node")
-        .put("node.local", true)
-        .put("discovery.zen.ping.multicast.enabled", false)
-        .put("index.store.fs.memory.enabled", true)
-        .put("index.gateway.type", "none")
-        .put("index.max_result_window", Integer.MAX_VALUE)
-        .put("gateway.type", "default")
-        .put("http.port", 0)
-        .put("discovery.zen.ping.unicast.hosts", "[\"localhost\"]")
-        .put("path.home", elasticDirPath.toAbsolutePath())
-        .put("path.data", elasticDirPath.resolve("data").toAbsolutePath())
-        .put("path.work", elasticDirPath.resolve("work").toAbsolutePath())
-        .put("path.logs", elasticDirPath.resolve("logs").toAbsolutePath())
-        .put("transport.tcp.connect_timeout", "60s")
-        .build();
-
-    // Start the node
-    node = NodeBuilder.nodeBuilder()
-        .settings(settings)
-        .node();
-
-    // Wait for it to be ready
-    node.client()
-        .admin()
-        .cluster()
-        .prepareHealth()
-        .setWaitForYellowStatus()
-        .execute()
-        .actionGet();
+    nodeInfo = ElasticTestUtils.startElasticsearchNode();
 
     createIndexes();
-
-    assertThat(node.isClosed()).isFalse();
-    port = getHttpPort();
   }
 
   @After
   public void cleanupIndex() {
-    node.client().admin().indices().prepareDelete(INDEX_NAME).execute();
-    createIndexes();
+    if (nodeInfo != null) {
+      ElasticTestUtils.deleteIndexes(nodeInfo.node, INDEX_NAME);
+      createIndexes();
+    }
   }
 
   @AfterClass
   public static void stopElasticsearchServer() {
-    if (node != null) {
-      node.close();
-      node = null;
-    }
-    if (elasticDir != null && elasticDir.delete()) {
-      elasticDir = null;
+    if (nodeInfo != null) {
+      nodeInfo.node.close();
+      nodeInfo.elasticDir.delete();
+      nodeInfo = null;
     }
   }
 
@@ -138,11 +75,7 @@
   protected Injector createInjector() {
     Config elasticsearchConfig = new Config(config);
     InMemoryModule.setDefaults(elasticsearchConfig);
-    elasticsearchConfig.setEnum("index", null, "type", IndexType.ELASTICSEARCH);
-    elasticsearchConfig.setString("index", null, "protocol", "http");
-    elasticsearchConfig.setString("index", null, "hostname", "localhost");
-    elasticsearchConfig.setString("index", null, "port", port);
-    elasticsearchConfig.setBoolean("index", "elasticsearch", "test", true);
+    ElasticTestUtils.configure(elasticsearchConfig, nodeInfo.port);
     return Guice.createInjector(
         new InMemoryModule(elasticsearchConfig, notesMigration));
   }
@@ -154,35 +87,19 @@
         new ChangeMapping(ChangeSchemaDefinitions.INSTANCE.getLatest());
     openChangesMapping.closedChanges = null;
     closedChangesMapping.openChanges = null;
-    node.client()
+    nodeInfo.node
+        .client()
         .admin()
         .indices()
         .prepareCreate(INDEX_NAME)
-        .addMapping(OPEN_CHANGES, gson.toJson(openChangesMapping))
-        .addMapping(CLOSED_CHANGES, gson.toJson(closedChangesMapping))
+        .addMapping(OPEN_CHANGES,
+            ElasticTestUtils.gson.toJson(openChangesMapping))
+        .addMapping(CLOSED_CHANGES,
+            ElasticTestUtils.gson.toJson(closedChangesMapping))
         .execute()
         .actionGet();
   }
 
-  private static String getHttpPort()
-      throws InterruptedException, ExecutionException {
-    String nodes = node.client().admin().cluster()
-        .nodesInfo(new NodesInfoRequest("*")).get().toString();
-    Gson gson = new GsonBuilder()
-        .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
-        .create();
-    Info info = gson.fromJson(nodes, Info.class);
-
-    checkState(info.nodes != null && info.nodes.size() == 1);
-    Iterator<NodeInfo> values = info.nodes.values().iterator();
-    String httpAddress = values.next().httpAddress;
-
-    checkState(
-        !Strings.isNullOrEmpty(httpAddress) && httpAddress.indexOf(':') > 0);
-    return httpAddress.substring(httpAddress.indexOf(':') + 1,
-        httpAddress.length());
-  }
-
   @Test
   public void byOwnerInvalidQuery() throws Exception {
     TestRepository<Repo> repo = createProject("repo");
diff --git a/gerrit-elasticsearch/src/test/java/com/google/gerrit/elasticsearch/ElasticTestUtils.java b/gerrit-elasticsearch/src/test/java/com/google/gerrit/elasticsearch/ElasticTestUtils.java
new file mode 100644
index 0000000..7c26edc
--- /dev/null
+++ b/gerrit-elasticsearch/src/test/java/com/google/gerrit/elasticsearch/ElasticTestUtils.java
@@ -0,0 +1,144 @@
+// Copyright (C) 2016 The Android Open Source Project
+//
+// Licensed 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 com.google.gerrit.elasticsearch;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.base.Strings;
+import com.google.common.io.Files;
+import com.google.gerrit.server.index.IndexModule.IndexType;
+import com.google.gson.FieldNamingPolicy;
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+
+import org.eclipse.jgit.lib.Config;
+import org.elasticsearch.action.admin.cluster.node.info.NodesInfoRequest;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.node.Node;
+import org.elasticsearch.node.NodeBuilder;
+
+import java.io.File;
+import java.nio.file.Path;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.concurrent.ExecutionException;
+
+final class ElasticTestUtils {
+  static final Gson gson = new GsonBuilder()
+      .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
+      .create();
+
+  static class ElasticNodeInfo {
+    final Node node;
+    final String port;
+    final File elasticDir;
+
+    private ElasticNodeInfo(Node node, File rootDir, String port) {
+      this.node = node;
+      this.port = port;
+      this.elasticDir = rootDir;
+    }
+  }
+
+  static void configure(Config config, String port) {
+    config.setEnum("index", null, "type", IndexType.ELASTICSEARCH);
+    config.setString("index", null, "protocol", "http");
+    config.setString("index", null, "hostname", "localhost");
+    config.setString("index", null, "port", port);
+    config.setBoolean("index", "elasticsearch", "test", true);
+  }
+
+  static ElasticNodeInfo startElasticsearchNode()
+      throws InterruptedException, ExecutionException {
+    File elasticDir = Files.createTempDir();
+    Path elasticDirPath = elasticDir.toPath();
+    Settings settings = Settings.settingsBuilder()
+        .put("cluster.name", "gerrit")
+        .put("node.name", "Gerrit Elasticsearch Test Node")
+        .put("node.local", true)
+        .put("discovery.zen.ping.multicast.enabled", false)
+        .put("index.store.fs.memory.enabled", true)
+        .put("index.gateway.type", "none")
+        .put("index.max_result_window", Integer.MAX_VALUE)
+        .put("gateway.type", "default")
+        .put("http.port", 0)
+        .put("discovery.zen.ping.unicast.hosts", "[\"localhost\"]")
+        .put("path.home", elasticDirPath.toAbsolutePath())
+        .put("path.data", elasticDirPath.resolve("data").toAbsolutePath())
+        .put("path.work", elasticDirPath.resolve("work").toAbsolutePath())
+        .put("path.logs", elasticDirPath.resolve("logs").toAbsolutePath())
+        .put("transport.tcp.connect_timeout", "60s")
+        .build();
+
+    // Start the node
+    Node node = NodeBuilder.nodeBuilder()
+        .settings(settings)
+        .node();
+
+    // Wait for it to be ready
+    node.client()
+        .admin()
+        .cluster()
+        .prepareHealth()
+        .setWaitForYellowStatus()
+        .execute()
+        .actionGet();
+
+    assertThat(node.isClosed()).isFalse();
+    return new ElasticNodeInfo(node, elasticDir, getHttpPort(node));
+  }
+
+  static void deleteIndexes(Node node, String index) {
+    node.client().admin().indices().prepareDelete(index).execute();
+  }
+
+  static class NodeInfo {
+    String httpAddress;
+  }
+
+  static class Info {
+    Map<String, NodeInfo> nodes;
+  }
+
+  private static String getHttpPort(Node node)
+      throws InterruptedException, ExecutionException {
+    String nodes = node.client().admin().cluster()
+        .nodesInfo(new NodesInfoRequest("*")).get().toString();
+    Gson gson = new GsonBuilder()
+        .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
+        .create();
+    Info info = gson.fromJson(nodes, Info.class);
+    if (info.nodes == null || info.nodes.size() != 1) {
+      throw new RuntimeException(
+          "Cannot extract local Elasticsearch http port");
+    }
+    Iterator<NodeInfo> values = info.nodes.values().iterator();
+    String httpAddress = values.next().httpAddress;
+    if (Strings.isNullOrEmpty(httpAddress)) {
+      throw new RuntimeException(
+          "Cannot extract local Elasticsearch http port");
+    }
+    if (httpAddress.indexOf(':') < 0) {
+      throw new RuntimeException(
+          "Seems that port is not included in Elasticsearch http_address");
+    }
+    return httpAddress.substring(httpAddress.indexOf(':') + 1,
+        httpAddress.length());
+  }
+
+  private ElasticTestUtils() {
+    // hide default constructor
+  }
+}