diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectCacheClock.java b/gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectCacheClock.java
new file mode 100644
index 0000000000..f86562cf50
--- /dev/null
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectCacheClock.java
@@ -0,0 +1,78 @@
+// Copyright (C) 2012 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.server.project;
+
+import com.google.gerrit.server.config.ConfigUtil;
+import com.google.gerrit.server.config.GerritServerConfig;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+
+import org.eclipse.jgit.lib.Config;
+
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/** Ticks periodically to force refresh events for {@link ProjectCacheImpl}. */
+@Singleton
+public class ProjectCacheClock {
+  private volatile long generation;
+
+  @Inject
+  public ProjectCacheClock(@GerritServerConfig Config serverConfig) {
+    this(TimeUnit.MILLISECONDS.convert(
+        ConfigUtil.getTimeUnit(serverConfig,
+            "cache", "projects", "checkFrequency",
+            5, TimeUnit.MINUTES), TimeUnit.MINUTES));
+  }
+
+  public ProjectCacheClock(long checkFrequencyMillis) {
+    if (10 < checkFrequencyMillis) {
+      // Start with generation 1 (to avoid magic 0 below).
+      generation = 1;
+      ThreadFactory factory = new ThreadFactory() {
+        private final AtomicInteger id = new AtomicInteger();
+
+        @Override
+        public Thread newThread(Runnable runnable) {
+          Thread thread = Executors.defaultThreadFactory().newThread(runnable);
+          thread.setName(String.format("ProjectCacheClock-%d", id.incrementAndGet()));
+          thread.setDaemon(true);
+          thread.setPriority(Thread.MIN_PRIORITY);
+          return thread;
+        }
+      };
+      ScheduledExecutorService executor = Executors.newScheduledThreadPool(1, factory);
+      executor.scheduleAtFixedRate(new Runnable() {
+        @Override
+        public void run() {
+          // This is not exactly thread-safe, but is OK for our use.
+          // The only thread that writes the volatile is this task.
+          generation = generation + 1;
+        }
+      }, checkFrequencyMillis, checkFrequencyMillis, TimeUnit.MILLISECONDS);
+    } else {
+      // Magic generation 0 triggers ProjectState to always
+      // check on each needsRefresh() request we make to it.
+      generation = 0;
+    }
+  }
+
+  long read() {
+    return generation;
+  }
+}
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectCacheImpl.java b/gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectCacheImpl.java
index ff687203ec..7a7f56e9da 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectCacheImpl.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/project/ProjectCacheImpl.java
@@ -19,8 +19,6 @@ import com.google.gerrit.server.cache.Cache;
 import com.google.gerrit.server.cache.CacheModule;
 import com.google.gerrit.server.cache.EntryCreator;
 import com.google.gerrit.server.config.AllProjectsName;
-import com.google.gerrit.server.config.ConfigUtil;
-import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.git.ProjectConfig;
 import com.google.inject.Inject;
@@ -30,7 +28,6 @@ import com.google.inject.TypeLiteral;
 import com.google.inject.name.Named;
 
 import org.eclipse.jgit.errors.RepositoryNotFoundException;
-import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.Repository;
 
 import java.util.Collections;
@@ -38,8 +35,6 @@ import java.util.Iterator;
 import java.util.NoSuchElementException;
 import java.util.SortedSet;
 import java.util.TreeSet;
-import java.util.concurrent.Executors;
-import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 
@@ -71,39 +66,19 @@ public class ProjectCacheImpl implements ProjectCache {
   private final Cache<Project.NameKey, ProjectState> byName;
   private final Cache<ListKey,SortedSet<Project.NameKey>> list;
   private final Lock listLock;
-  private volatile long generation;
+  private final ProjectCacheClock clock;
 
   @Inject
   ProjectCacheImpl(
       final AllProjectsName allProjectsName,
       @Named(CACHE_NAME) final Cache<Project.NameKey, ProjectState> byName,
       @Named(CACHE_LIST) final Cache<ListKey, SortedSet<Project.NameKey>> list,
-      @GerritServerConfig final Config serverConfig) {
+      ProjectCacheClock clock) {
     this.allProjectsName = allProjectsName;
     this.byName = byName;
     this.list = list;
     this.listLock = new ReentrantLock(true /* fair */);
-
-    long checkFrequencyMillis = TimeUnit.MILLISECONDS.convert(
-        ConfigUtil.getTimeUnit(serverConfig,
-            "cache", "projects", "checkFrequency",
-            5, TimeUnit.MINUTES), TimeUnit.MINUTES);
-    if (10 < checkFrequencyMillis) {
-      // Start with generation 1 (to avoid magic 0 below).
-      generation = 1;
-      Executors.newScheduledThreadPool(1).scheduleAtFixedRate(new Runnable() {
-        @Override
-        public void run() {
-          // This is not exactly thread-safe, but is OK for our use.
-          // The only thread that writes the volatile is this task.
-          generation = generation + 1;
-        }
-      }, checkFrequencyMillis, checkFrequencyMillis, TimeUnit.MILLISECONDS);
-    } else {
-      // Magic generation 0 triggers ProjectState to always
-      // check on each needsRefresh() request we make to it.
-      generation = 0;
-    }
+    this.clock = clock;
   }
 
   @Override
@@ -125,7 +100,7 @@ public class ProjectCacheImpl implements ProjectCache {
    */
   public ProjectState get(final Project.NameKey projectName) {
     ProjectState state = byName.get(projectName);
-    if (state != null && state.needsRefresh(generation)) {
+    if (state != null && state.needsRefresh(clock.read())) {
       byName.remove(projectName);
       state = byName.get(projectName);
     }