验证用Moq调用的方法

试图验证一个方法正在模拟中被调用，但似乎无法弄清楚为什么我一直得到一个异常抛出，它没有被调用。所讨论的方法如下:

public class CustomerSyncEngine {
public CustomerSyncEngine(ILoggingProvider loggingProvider, ICrmProvider crmProvider, ICacheProvider cacheProvider) {
  Logger = loggingProvider;
  CrmProvider = crmProvider;
  CacheProvider = cacheProvider;
}
public virtual void SyncPickLists() {
  Logger.LogBeginPicklistSync();
  // get all the pick lists from the local cache
  var localCachePickLists = CacheProvider.GetPickLists().ToList();
  // get all the pick lists from the remote system
  var crmPickLists = CrmProvider.GetPickLists().ToList();
  // build a sync plan
  var changes = BuildPickListUpdatePlan(localCachePickLists, crmPickLists).ToList();
  // run the sync
  RunPickListSync(changes);
  Logger.LogEndPicklistSync();
}
}

然后我写了这样一个测试:

[TestMethod]
public void TestSyncPickLists() {
  // arrange
  var mockCrm = new Mock<ICrmProvider>();
  mockCrm.Verify(x => x.GetPickLists(), Times.Once(), "ICrmProvider.GetPickLists not called");
  var mockCache = Mock.Of<ICacheProvider>();
  var mockLogger = Mock.Of<ILoggingProvider>();
  // act
  var syncEngine = new CustomerSyncEngine(mockLogger, mockCrm.Object, mockCache);
  syncEngine.SyncPickLists();
  // assert
  mockCrm.VerifyAll();
}

当我运行它时，测试失败，并显示我在Verify()中指定的消息。所以我设置了一堆断点，我看到测试从不调用syncEngine.SyncPickLists()方法，这让我感到困惑。所以我注释掉了两个Verify() &VerifyAll()语句，现在我看到正确调用的东西。我遗漏了什么?看起来我正在做的正是在快速入门以及这个线程中所显示的。