单元测试mock当前时间

• 2019 年 10 月 10 日
• 笔记

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  {      /// <summary>      /// 获取当前时间      /// However, when unit testing with static state, always remember to tear down your fixture by calling .      /// </summary>      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<TimeProvider>();  timeMock.SetupGet(tp => tp.Now).Returns(new DateTime(2010, 3, 11));  TimeProvider.Current = timeMock.Object;

需要用到moq4模拟对象