问如何对属性更改事件进行单元测试

EN

[Export(typeof(IDriveTimeService))]
public class DriveTimeService : IDriveTimeService
{
    public void Initialize(IHasDriveTimes target)
    {
        var _driveTimeService = new DriveTimeService ();
        new DriveTimesManager(target);
    }
}

public DriveTimesManager(IHasDriveTimes target)
{
    if (target != null)
    {
        target.PropertyChanged += HandleDriveTimesChanged;
    }
}

private void HandleDriveTimesChanged(object sender, PropertyChangedEventArgs e)
{
    var driveTimes = sender as IHasDriveTimes;
    if (driveTimes != null)
    {
        if (e.PropertyName == driveTimes.GetPropertyName(t => t.StartDateTime))
        {
            driveTimes.StopDateTime += driveTimes.StartDateTime - _previousStartDateTime;
            _previousStartDateTime = driveTimes.StartDateTime;
        }

    }
}

[TestClass]
public class DriveTimeServiceTest
{
    [TestMethod]
    public void DriveTimeServiceNullTest()
    {
        var driveTimeService = new DriveTimeService();


        driveTimeService.Initialize(null);                
        Assert.IsNotNull(driveTimeService);
    }

    [TestMethod]
    public void DriveTimeManagerTest()
    {
        var propertyName = "";
        var mock = new Mock<IHasDriveTimes>();
        DriveTimesManager manager = new DriveTimesManager(mock.Object);

        var change = new PropertyChangedEventArgs(propertyName);
        mock.Verify(m => m.StartDateTime);
        mock.Verify(m => m.StopDateTime);

        manager.HandleDriveTimesChanged(manager, change);

    }

}