假设我们如下代码调用了HttpContext.Current.Cache
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public class CacheManager
{ public static HttpContext mHttpContext = HttpContext.Current;
public void SetCache<t>(string key, T value)
{
mHttpContext.Cache.Insert(key, value, null, DateTime.MaxValue, new TimeSpan(0, 100, 0));
}
public T GetCache<t>(string key)
{
return (T)mHttpContext.Cache.Get(key);
}
}</t></t> |
现在我有一个类调用了上面的GetCache<T>
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public class LanguageController
{ private CacheManager cacheManger = new CacheManager();
public string Get_UserLanguage()
{
string userLanguage=cacheManger.GetCache<string>("userLanguage");
if (!string.IsNullOrEmpty(userLanguage)) return userLanguage;
return "zh-CN";
}
}</string>
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[TestMethod]public void Test_Get_UserLanguage()
{ CacheManager cacheManger = new CacheManager();
cacheManger.SetCache<string>("userLanguage", "en-GB");
LanguageController languageController = new LanguageController();
Assert.AreEqual(languageController.Get_UserLanguage(), "en-GB");
}</string>
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System.NullReferenceException: Object reference not set to an instance of an object.
跟踪调试，发现下面方法这句mHttpContext.Cache为空
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public void SetCache<t>(string key, T value)
{ mHttpContext.Cache.Insert(key, value, null, DateTime.MaxValue, new TimeSpan(0, 100, 0));
}</t> |
现在，将测试代码改为如下：
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[TestMethod]public void Test_Get_Language_By_Fake()
{ HttpContext.Current = new HttpContext(new HttpRequest(null,
"http://10.10.50.127/RGV2/devtest1", null), new HttpResponse(null));
CacheManager.mHttpContext = HttpContext.Current;
CacheManager cacheManger = new CacheManager();
cacheManger.SetCache<string>("userLanguage", "en-GB");
LanguageController languageController = new LanguageController();
Assert.AreEqual(languageController.Get_UserLanguage(), "en-GB");
}</string>
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测试通过：
总结，当我们测试的包含HttpContext.Current.Cache代码时：
1. 将HttpContext.Current.Cache 公布为类的静态属性，这样测试时，一个地方改了，全部就改过来了
2. 用下面的代码来给HttpContext.Current赋值
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HttpContext.Current = new HttpContext(new HttpRequest(null,
"http://10.10.50.127/RGV2/devtest1", null), new HttpResponse(null));
CacheManager.mHttpContext = HttpContext.Current; |
3. 建议所有调用HttpContext获得值的地方，尽量公布为属性，这样方便测试,比如如下的代码我们就直接赋值了,这个和本文关系不大，只是一个实践而已。
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public class ConfigController
{
private string tempConfigPath;
public string mConfigPath
{
get
{
if (tempConfigPath == null)
{
tempConfigPath = HttpContext.Current.Server.MapPath(@"~/App_Data/config.xml");
}
return tempConfigPath;
}
set
{
tempConfigPath = value;
}
}
} |
4. 我们也可以使用Mock，但是个人认为上面的方法更简单点。
本文转自敏捷的水博客园博客，原文链接http://www.cnblogs.com/cnblogsfans/archive/2009/08/05/1539788.html如需转载请自行联系原作者
王德水