在实际项目中很多地方用到DateTime.Now，这个时间是时时变化的。如果要进行单元测试对比预期结果时，这个时间无法预测，可以添加如下两个时间类

namespace Common.Helper{    /// 
    /// 获取当前时间    /// However, when unit testing with static state, always remember to tear down your fixture by calling .    /// 
    public abstract class TimeProvider    {        private static TimeProvider current =            DefaultTimeProvider.Instance;        public static TimeProvider Current        {            get { return TimeProvider.current; }            set            {                if (value == null)                {                    throw new ArgumentNullException("value");                }                TimeProvider.current = value;            }        }        public abstract DateTime Now { get; }        public static void ResetToDefault()        {            TimeProvider.current = DefaultTimeProvider.Instance;        }    }    public class DefaultTimeProvider : TimeProvider    {        private readonly static DefaultTimeProvider instance =            new DefaultTimeProvider();        private DefaultTimeProvider() { }        public override DateTime Now        {            get { return DateTime.Now; }        }        public static DefaultTimeProvider Instance        {            get { return DefaultTimeProvider.instance; }        }    }}

在实际代码中使用方法：

var now = TimeProvider.Current.Now;

单元测试模拟方法：

var timeMock = new Mock
     
      ();timeMock.SetupGet(tp => tp.Now).Returns(new DateTime(2010, 3, 11));TimeProvider.Current = timeMock.Object;
     

 

需要用到moq4模拟对象