diff --git a/src/test/java/com/ericsson/gerrit/plugins/highavailability/autoreindex/ChangeReindexRunnableTest.java b/src/test/java/com/ericsson/gerrit/plugins/highavailability/autoreindex/ChangeReindexRunnableTest.java
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+// Copyright (C) 2021 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.ericsson.gerrit.plugins.highavailability.autoreindex;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.Mockito.lenient;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.ericsson.gerrit.plugins.highavailability.forwarder.ForwardedIndexChangeHandler;
+import com.ericsson.gerrit.plugins.highavailability.forwarder.ForwardedIndexingHandler.Operation;
+import com.ericsson.gerrit.plugins.highavailability.forwarder.rest.AbstractIndexRestApiServlet;
+import com.google.common.collect.ImmutableSortedSet;
+import com.google.gerrit.entities.Account;
+import com.google.gerrit.entities.BranchNameKey;
+import com.google.gerrit.entities.Change;
+import com.google.gerrit.server.config.AllUsersName;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.group.db.Groups;
+import com.google.gerrit.server.notedb.ChangeNotes;
+import com.google.gerrit.server.notedb.ChangeNotes.Factory.ChangeNotesResult;
+import com.google.gerrit.server.project.ProjectCache;
+import com.google.gerrit.server.util.OneOffRequestContext;
+import java.sql.Timestamp;
+import java.time.LocalDateTime;
+import java.time.ZoneOffset;
+import java.util.Optional;
+import java.util.stream.Stream;
+import org.eclipse.jgit.lib.Repository;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+@RunWith(MockitoJUnitRunner.class)
+public class ChangeReindexRunnableTest {
+
+  @Mock private ForwardedIndexChangeHandler indexer;
+  @Mock private IndexTs indexTs;
+  @Mock private OneOffRequestContext ctx;
+  @Mock private ProjectCache projectCache;
+  @Mock private Groups groups;
+  @Mock private GitRepositoryManager repoManager;
+  @Mock private AllUsersName allUsers;
+  @Mock private ChangeNotes.Factory changeNotesFactory;
+  @Mock private Repository repo;
+  @Mock private ChangeNotesResult changeNotesRes;
+  @Mock private ChangeNotes changeNotes;
+
+  private ChangeReindexRunnable changeReindexRunnable;
+
+  @Before
+  public void setUp() throws Exception {
+    changeReindexRunnable =
+        new ChangeReindexRunnable(
+            indexer, indexTs, ctx, projectCache, repoManager, changeNotesFactory);
+  }
+
+  @Test
+  public void changeIsIndexedWhenItIsCreatedAfterLastChangeReindex() throws Exception {
+    Timestamp currentTime = Timestamp.valueOf(LocalDateTime.now());
+    Timestamp afterCurrentTime = new Timestamp(currentTime.getTime() + 1000L);
+    Change change = newChange(afterCurrentTime);
+
+    Optional<Timestamp> changeLastTs = changeReindexRunnable.indexIfNeeded(change, currentTime);
+    assertThat(changeLastTs.isPresent()).isTrue();
+    assertThat(changeLastTs.get()).isEqualTo(afterCurrentTime);
+    verify(indexer).index(changeProjectIndexKey(change), Operation.INDEX, Optional.empty());
+  }
+
+  @Test
+  public void changeIsIndexedDuringRun() throws Exception {
+    LocalDateTime currentTime = LocalDateTime.now(ZoneOffset.UTC);
+    Timestamp afterCurrentTime =
+        new Timestamp(currentTime.toEpochSecond(ZoneOffset.UTC) * 1000 + 1000L);
+    Change change = newChange(afterCurrentTime);
+
+    when(indexTs.getUpdateTs(AbstractIndexRestApiServlet.IndexName.CHANGE))
+        .thenReturn(Optional.of(currentTime));
+    when(projectCache.all()).thenReturn(ImmutableSortedSet.of(change.getProject()));
+    when(repoManager.openRepository(change.getProject())).thenReturn(repo);
+    when(changeNotesFactory.scan(repo, change.getProject())).thenReturn(Stream.of(changeNotesRes));
+    lenient().when(changeNotesRes.error()).thenReturn(Optional.empty());
+    when(changeNotesRes.notes()).thenReturn(changeNotes);
+    when(changeNotes.getChange()).thenReturn(change);
+
+    changeReindexRunnable.run();
+
+    verify(indexer).index(changeProjectIndexKey(change), Operation.INDEX, Optional.empty());
+  }
+
+  @Test
+  public void groupIsNotIndexedWhenItIsCreatedBeforeLastGroupReindex() throws Exception {
+    Timestamp currentTime = Timestamp.valueOf(LocalDateTime.now());
+    Timestamp beforeCurrentTime = new Timestamp(currentTime.getTime() - 1000L);
+    Change change = newChange(beforeCurrentTime);
+
+    Optional<Timestamp> changeLastTs = changeReindexRunnable.indexIfNeeded(change, currentTime);
+    assertThat(changeLastTs.isPresent()).isFalse();
+    verify(indexer, never())
+        .index(changeProjectIndexKey(change), Operation.INDEX, Optional.empty());
+  }
+
+  private String changeProjectIndexKey(Change change) {
+    return change.getProject() + "~" + change.getChangeId();
+  }
+
+  private Change newChange(Timestamp changeTs) {
+    return new Change(
+        Change.key("changekey"),
+        Change.id(123),
+        Account.id(1000000),
+        BranchNameKey.create("projectname", "main"),
+        changeTs);
+  }
+}