diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorage.java b/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorage.java
index e75e55b..370d48b 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorage.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorage.java
@@ -205,7 +205,8 @@
     }
   }
 
-  private class Task {
+  @VisibleForTesting
+  class Task {
     public final ReplicateRefUpdate update;
     public final String json;
     public final String taskKey;
diff --git a/src/test/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorageTaskTest.java b/src/test/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorageTaskTest.java
new file mode 100644
index 0000000..ca69644
--- /dev/null
+++ b/src/test/java/com/googlesource/gerrit/plugins/replication/ReplicationTasksStorageTaskTest.java
@@ -0,0 +1,380 @@
+// Copyright (C) 2020 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.googlesource.gerrit.plugins.replication;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import com.google.common.jimfs.Configuration;
+import com.google.common.jimfs.Jimfs;
+import com.googlesource.gerrit.plugins.replication.ReplicationTasksStorage.ReplicateRefUpdate;
+import com.googlesource.gerrit.plugins.replication.ReplicationTasksStorage.Task;
+import java.net.URISyntaxException;
+import java.nio.file.FileSystem;
+import java.nio.file.Files;
+import org.eclipse.jgit.transport.URIish;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class ReplicationTasksStorageTaskTest {
+  protected static final String PROJECT = "myProject";
+  protected static final String REF = "myRef";
+  protected static final String REMOTE = "myDest";
+  protected static final URIish URISH = getUrish("http://example.com/" + PROJECT + ".git");
+  protected static final ReplicateRefUpdate REF_UPDATE =
+      new ReplicateRefUpdate(PROJECT, REF, URISH, REMOTE);
+
+  protected ReplicationTasksStorage tasksStorage;
+  protected FileSystem fileSystem;
+
+  @Before
+  public void setUp() throws Exception {
+    fileSystem = Jimfs.newFileSystem(Configuration.unix());
+    tasksStorage = new ReplicationTasksStorage(fileSystem.getPath("replication_site"));
+  }
+
+  @After
+  public void tearDown() throws Exception {
+    fileSystem.close();
+  }
+
+  @Test
+  public void createdTaskIsWaiting() throws Exception {
+    Task original = tasksStorage.new Task(REF_UPDATE);
+    assertNotWaiting(original);
+
+    Task persistedView = tasksStorage.new Task(REF_UPDATE);
+    assertNotWaiting(persistedView);
+
+    original.create();
+    assertIsWaiting(original);
+    assertIsWaiting(persistedView);
+  }
+
+  @Test
+  public void startedTaskIsRunning() throws Exception {
+    Task original = tasksStorage.new Task(REF_UPDATE);
+
+    original.create();
+    original.start();
+    assertNotWaiting(original);
+    assertIsRunning(original);
+
+    Task persistedView = tasksStorage.new Task(REF_UPDATE);
+    assertNotWaiting(persistedView);
+    assertIsRunning(persistedView);
+  }
+
+  @Test
+  public void resetTaskIsWaiting() throws Exception {
+    Task original = tasksStorage.new Task(REF_UPDATE);
+
+    original.create();
+    original.start();
+    original.reset();
+    assertIsWaiting(original);
+    assertNotRunning(original);
+
+    Task persistedView = tasksStorage.new Task(REF_UPDATE);
+    assertIsWaiting(persistedView);
+    assertNotRunning(persistedView);
+  }
+
+  @Test
+  public void finishedTaskIsRemoved() throws Exception {
+    Task original = tasksStorage.new Task(REF_UPDATE);
+
+    original.create();
+    original.start();
+    original.finish();
+    assertNotWaiting(original);
+    assertNotRunning(original);
+
+    Task persistedView = tasksStorage.new Task(REF_UPDATE);
+    assertNotWaiting(persistedView);
+    assertNotRunning(persistedView);
+  }
+
+  @Test
+  public void createWaitingTaskIsDeduped() throws Exception {
+    Task original = tasksStorage.new Task(REF_UPDATE);
+    String key = original.create();
+
+    Task secondUpdate = tasksStorage.new Task(REF_UPDATE);
+    assertEquals(secondUpdate.create(), key);
+    assertIsWaiting(secondUpdate);
+    assertIsWaiting(original);
+  }
+
+  @Test
+  public void createWaitingTaskWhileTaskIsRunning() throws Exception {
+    Task original = tasksStorage.new Task(REF_UPDATE);
+    original.create();
+    original.start();
+    assertIsRunning(original);
+
+    Task secondUpdate = tasksStorage.new Task(REF_UPDATE);
+    secondUpdate.create();
+
+    assertIsWaiting(secondUpdate);
+    assertIsRunning(original);
+  }
+
+  @Test
+  public void canCompleteTwoTasks() throws Exception {
+    Task original = tasksStorage.new Task(REF_UPDATE);
+    original.create();
+    original.start();
+    original.finish();
+
+    Task secondUpdate = tasksStorage.new Task(REF_UPDATE);
+    secondUpdate.create();
+    assertIsWaiting(secondUpdate);
+    secondUpdate.start();
+    assertIsRunning(secondUpdate);
+    secondUpdate.finish();
+    assertNotWaiting(secondUpdate);
+    assertNotRunning(secondUpdate);
+  }
+
+  @Test
+  public void canStartResetTask() throws Exception {
+    Task original = tasksStorage.new Task(REF_UPDATE);
+
+    original.create();
+    original.start();
+    original.reset();
+
+    Task persistedView = tasksStorage.new Task(REF_UPDATE);
+    persistedView.start();
+    assertIsRunning(persistedView);
+    assertIsRunning(original);
+  }
+
+  @Test
+  public void canResetPreviouslyResetAndStartedTask() throws Exception {
+    Task original = tasksStorage.new Task(REF_UPDATE);
+
+    original.create();
+    original.start();
+    original.reset();
+
+    Task persistedView = tasksStorage.new Task(REF_UPDATE);
+    persistedView.start();
+    persistedView.reset();
+    assertIsWaiting(persistedView);
+    assertIsWaiting(original);
+  }
+
+  @Test
+  public void multipleActorsCanUpdateSameTask() throws Exception {
+    Task persistedView = tasksStorage.new Task(REF_UPDATE);
+
+    Task fromEvent = tasksStorage.new Task(REF_UPDATE);
+    fromEvent.create();
+    assertIsWaiting(persistedView);
+
+    Task fromPusherStart = tasksStorage.new Task(REF_UPDATE);
+    fromPusherStart.start();
+    assertIsRunning(persistedView);
+
+    Task fromPusherEnd = tasksStorage.new Task(REF_UPDATE);
+    fromPusherEnd.finish();
+    assertNotWaiting(persistedView);
+    assertNotRunning(persistedView);
+  }
+
+  @Test
+  public void canHaveTwoWaitingTasksForDifferentRefs() throws Exception {
+    Task updateA = tasksStorage.new Task(new ReplicateRefUpdate(PROJECT, "refA", URISH, REMOTE));
+    Task updateB = tasksStorage.new Task(new ReplicateRefUpdate(PROJECT, "refB", URISH, REMOTE));
+    updateA.create();
+    updateB.create();
+    assertIsWaiting(updateA);
+    assertIsWaiting(updateB);
+  }
+
+  @Test
+  public void canHaveTwoRunningTasksForDifferentRefs() throws Exception {
+    Task updateA = tasksStorage.new Task(new ReplicateRefUpdate(PROJECT, "refA", URISH, REMOTE));
+    Task updateB = tasksStorage.new Task(new ReplicateRefUpdate(PROJECT, "refB", URISH, REMOTE));
+    updateA.create();
+    updateB.create();
+    updateA.start();
+    updateB.start();
+    assertIsRunning(updateA);
+    assertIsRunning(updateB);
+  }
+
+  @Test
+  public void canHaveTwoWaitingTasksForDifferentProjects() throws Exception {
+    Task updateA =
+        tasksStorage
+        .new Task(
+            new ReplicateRefUpdate(
+                "projectA", REF, getUrish("http://example.com/projectA.git"), REMOTE));
+    Task updateB =
+        tasksStorage
+        .new Task(
+            new ReplicateRefUpdate(
+                "projectB", REF, getUrish("http://example.com/projectB.git"), REMOTE));
+    updateA.create();
+    updateB.create();
+    assertIsWaiting(updateA);
+    assertIsWaiting(updateB);
+  }
+
+  @Test
+  public void canHaveTwoRunningTasksForDifferentProjects() throws Exception {
+    Task updateA =
+        tasksStorage
+        .new Task(
+            new ReplicateRefUpdate(
+                "projectA", REF, getUrish("http://example.com/projectA.git"), REMOTE));
+    Task updateB =
+        tasksStorage
+        .new Task(
+            new ReplicateRefUpdate(
+                "projectB", REF, getUrish("http://example.com/projectB.git"), REMOTE));
+    updateA.create();
+    updateB.create();
+    updateA.start();
+    updateB.start();
+    assertIsRunning(updateA);
+    assertIsRunning(updateB);
+  }
+
+  @Test
+  public void canHaveTwoWaitingTasksForDifferentRemotes() throws Exception {
+    Task updateA = tasksStorage.new Task(new ReplicateRefUpdate(PROJECT, REF, URISH, "remoteA"));
+    Task updateB = tasksStorage.new Task(new ReplicateRefUpdate(PROJECT, REF, URISH, "remoteB"));
+    updateA.create();
+    updateB.create();
+    assertIsWaiting(updateA);
+    assertIsWaiting(updateB);
+  }
+
+  @Test
+  public void canHaveTwoRunningTasksForDifferentRemotes() throws Exception {
+    Task updateA = tasksStorage.new Task(new ReplicateRefUpdate(PROJECT, REF, URISH, "remoteA"));
+    Task updateB = tasksStorage.new Task(new ReplicateRefUpdate(PROJECT, REF, URISH, "remoteB"));
+    updateA.create();
+    updateB.create();
+    updateA.start();
+    updateB.start();
+    assertIsRunning(updateA);
+    assertIsRunning(updateB);
+  }
+
+  @Test
+  public void illegalFinishNonRunningTaskIsGraceful() throws Exception {
+    Task task = tasksStorage.new Task(REF_UPDATE);
+    task.finish();
+    assertNotWaiting(task);
+    assertNotRunning(task);
+  }
+
+  @Test
+  public void illegalResetNonRunningTaskIsGraceful() throws Exception {
+    Task task = tasksStorage.new Task(REF_UPDATE);
+    task.reset();
+    assertNotWaiting(task);
+    assertNotRunning(task);
+  }
+
+  @Test
+  public void illegalResetFinishedTaskIsGraceful() throws Exception {
+    Task task = tasksStorage.new Task(REF_UPDATE);
+
+    task.create();
+    task.start();
+    task.finish();
+    task.reset();
+    assertNotWaiting(task);
+    assertNotRunning(task);
+  }
+
+  @Test
+  public void illegalFinishFinishedTaskIsGraceful() throws Exception {
+    Task task = tasksStorage.new Task(REF_UPDATE);
+
+    task.create();
+    task.start();
+    task.finish();
+    task.finish();
+    assertNotWaiting(task);
+    assertNotRunning(task);
+  }
+
+  @Test
+  public void illegalFinishResetTaskIsGraceful() throws Exception {
+    Task original = tasksStorage.new Task(REF_UPDATE);
+
+    original.create();
+    original.start();
+    original.reset();
+
+    Task persistedView = tasksStorage.new Task(REF_UPDATE);
+    persistedView.finish();
+    assertIsWaiting(persistedView);
+  }
+
+  @Test
+  public void illegalResetResetTaskIsGraceful() throws Exception {
+    Task original = tasksStorage.new Task(REF_UPDATE);
+
+    original.create();
+    original.start();
+    original.reset();
+
+    Task persistedView = tasksStorage.new Task(REF_UPDATE);
+    persistedView.reset();
+    assertIsWaiting(persistedView);
+  }
+
+  private void assertIsWaiting(Task task) {
+    assertTrue(whiteBoxIsWaiting(task));
+  }
+
+  private void assertNotWaiting(Task task) {
+    assertFalse(whiteBoxIsWaiting(task));
+  }
+
+  private void assertIsRunning(Task task) {
+    assertTrue(whiteBoxIsRunning(task));
+  }
+
+  private void assertNotRunning(Task task) {
+    assertFalse(whiteBoxIsRunning(task));
+  }
+
+  private boolean whiteBoxIsRunning(Task task) {
+    return Files.exists(task.running);
+  }
+
+  private boolean whiteBoxIsWaiting(Task task) {
+    return Files.exists(task.waiting);
+  }
+
+  public static URIish getUrish(String uri) {
+    try {
+      return new URIish(uri);
+    } catch (URISyntaxException e) {
+      throw new RuntimeException("Cannot instantiate URIish object", e);
+    }
+  }
+}