What is “Mock You”系列之（五）：在实际环境中使用Moq

前面出于演示目的，使用的都是一个个小的示例代码。这里模拟一下使用Moq真实场景。

假设要写个蜘蛛，我们有个接口叫IHttpClient负责连接到指定网站，PageEntity用于存储抓取页面信息。SpiderEngine则负责通过IHttpClient将目标页面上XPath指定的内容存到PageEntity中。

现在要测试SpiderEngine，单元测试嘛，既然我们选择测试SpiderEngine，就尽量不要依赖IHttpClient的具体实现。我们通过Moq模拟IHttpClient的实现进而测试SpiderEngine。

 

 

IHttpClient.cs

namespace FirstTest.SampleClasses
{
    public interface IHttpClient
    {
        string Url { get; set; }
        string GetXpathContent(string xpathExp);
    }
}

PageEntity.cs

namespace FirstTest.SampleClasses
{
    public class PageEntity
    {
        public PageEntity() { Sid = Guid.NewGuid(); }

        public static PageEntity CreatePageEntity()
        {
            return new PageEntity { Sid = Guid.NewGuid() };
        }
        public Guid Sid { get; set; }
        public string Url { get; set; }
        public string XpathExp { get; set; }
        public string Content { get; set; }
    }
}

SpiderEngine.cs

namespace FirstTest.SampleClasses
{
    public class SpiderEngine
    {
        #region Constructors
        public SpiderEngine(IHttpClient client)
        {
            this.httpClient = client;
        }
        #endregion

        #region Fields
        private IHttpClient httpClient;
        #endregion

        public void BuildPage(ref PageEntity page)
        {
            if (string.IsNullOrEmpty(page.Url) || string.IsNullOrEmpty(page.XpathExp))
                throw new Exception("BuildPage must be configured");
            httpClient.Url = page.Url;
            page.Content = httpClient.GetXpathContent(page.XpathExp);
        }
    }
}

 

UnitTest

/// <summary>
        /// 演练：在实际项目中使用Moq
        /// </summary>
        //[TestMethod]
        [Owner("wJiang")]
        public void MoqInFact()
        {
            string url = "";
            //Mock IHttpClient Object
            var mo = new Mock<IHttpClient>();
            //Set its behaviors
            mo.Setup( p => p.GetXpathContent(It.IsAny<string>()))
                .Returns("Hello Cnblogs!" + mo.Object.Url)
                .Callback( () => url = mo.Object.Url );
            mo.SetupAllProperties();
            //procedure test
            SpiderEngine engine = new SpiderEngine(mo.Object);
            PageEntity page = new PageEntity { XpathExp = "\\items", Url = "http://www.wjiangathpc.spaceslive.com" };
            engine.BuildPage(ref page);
            //Asserts
            Assert.AreEqual(url, page.Url);
            Assert.AreEqual(page.Content, "Hello Cnblogs!");
        }