我对单元测试很新,想要在服务不可用时进行模拟/测试,以确保抛出正确的错误。
REST API,通过C#中的LDAP / DirectorySearcher查询Active Directory用户帐户。我看到三种可能的结果:找到用户,找不到用户,服务不可用(DirectorySearcher)。我为此设置了三个测试,但是一个总是失败,这取决于我是否连接到域。连接后,测试#1,#2成功。断开测试#2时,#3成功。我的测试是否过度杀伤,因为DirectoryServices库已经可靠了?我的目的是确保Web服务器在失去查询Active Directory的能力时抛出异常。
using System;
using System.Collections.Generic;
using System.DirectoryServices;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Runtime.InteropServices;
using System.Web.Http;
namespace IdentitiesApi.Controllers
{
public class UsersController : ApiController
{
// GET api/users/?username=admin
public SearchResult Get([FromUri]string userName)
{
using (var searcher = new DirectorySearcher())
{
searcher.Filter = string.Format("(&(objectClass=user)(sAMAccountName={0}))", userName);
try
{
SearchResult user = searcher.FindOne();
if (user == null)
{
var response = new HttpResponseMessage(HttpStatusCode.NotFound)
{
Content = new StringContent(string.Format("No user with username = \"{0}\" found.", userName)),
ReasonPhrase = "User Not Found"
};
throw new HttpResponseException(response);
}
else
{
return user;
}
}
catch (COMException)
{
var response = new HttpResponseMessage(HttpStatusCode.ServiceUnavailable)
{
Content = new StringContent("The directory service could not be contacted. Please try again later."),
ReasonPhrase = "Directory Service Unavailable"
};
throw new HttpResponseException(response);
}
}
}
}
}
using System;
using System.DirectoryServices;
using System.Linq;
using System.Net;
using System.Runtime.InteropServices;
using System.Web.Http;
using IdentitiesApi.Controllers;
using Microsoft.VisualStudio.TestTools.UnitTesting;
namespace IdentitiesApi.Test
{
[TestClass]
public class UsersTest
{
[TestMethod]
public void Single_AD_User()
{
// arrange
var controller = new UsersController();
SearchResult searchResult;
string userName = "admin"; // existing user name
string expected = "admin";
string actual = "";
// act
searchResult = controller.Get(userName);
// assert
foreach (object value in searchResult.Properties["samAccountName"])
{
actual = value.ToString();
}
Assert.AreEqual(expected, actual);
}
[TestMethod]
[ExpectedException(typeof(HttpResponseException))]
public void AD_User_Not_Found_Exception()
{
// arrange
var controller = new UsersController();
SearchResult searchResult;
string userName = "?"; // invalid user name
// act
try
{
searchResult = controller.Get(userName);
}
catch (HttpResponseException ex)
{
// assert
Assert.AreEqual(HttpStatusCode.NotFound, ex.Response.StatusCode);
throw;
}
}
[TestMethod]
[ExpectedException(typeof(HttpResponseException))]
public void AD_Service_Unavailable_Exception()
{
// arrange
var controller = new UsersController();
SearchResult searchResult;
string userName = "admin";
// act
searchResult = controller.Get(userName);
}
}
}
答案 0 :(得分:4)
测试类似这样的东西的最好方法是使用DirectorySearcher的依赖注入,然后在单元测试中使用mock。
看起来有一个IDirectorySearcher接口,虽然我不知道DirectorySearcher是否实现了它。无论如何,这可能超出了你的要求,这就是我的建议:
Keep your controllers lightweight。现在,您的行动中有大量不可重复使用的业务逻辑。您正在捕获COM异常,并且您的控制器“知道”低级AD工作。相反,我会编写一个包装器来处理它,并抛出一个通用异常。您可以避免大量重复的代码(两个异常的额外抛出),如果您更改了使用AD的方式,则可以在一个位置执行此操作。
将包装器注入控制器。这将允许您模拟服务,因此您可以通过您的操作测试所有不同的路径。
重写控制器:
public class UsersController : ApiController
{
private IDirectorySearcher _searcher;
public UsersController(IDirectorySearcher searcher)
{
_searcher = searcher;
}
// GET api/users/?username=admin
public SearchResult Get([FromUri]string userName)
{
try
{
return _searcher.FindSAMAccountName(userName);
}
catch (ADException ex)
{
var response = new HttpResponseMessage(HttpStatusCode.NotFound)
{
Content = ex.Content,
ReasonPhrase = ex.Reason
};
throw new HttpResponseException(response);
}
}
}
然后你的单元测试(在这种情况下,我使用moq作为我的模拟库):
[TestMethod]
[ExpectedException(typeof(HttpResponseException))]
public void AD_User_Not_Found_Exception()
{
var searcher = new Mock<IDirectorySearcher>();
searcher.Setup(x => x.FindSAMAccountName(It.IsAny<string>()).Throws(new ADException());
var controller = new UsersController(searcher.Object);
try
{
SearchResult searchResult = controller.Get("doesn't matter. any argument throws");
}
catch (HttpResponseException ex)
{
// assert
Assert.AreEqual(HttpStatusCode.NotFound, ex.Response.StatusCode);
throw;
}
}
使用模拟的好处在于,对于每个单元测试,您可以更改Setup()调用以返回您想要的任何内容。它可以返回SearchResult,或抛出异常,或者什么也不做。你甚至可以使用
searcher.Verify(x => x.FindSAMAccountName(It.IsAny<string>()), Times.Once())
验证调用恰好发生了一次(或者没有,或者其他什么)。
这可能比你要求的要多,但总的来说,每层的复杂性越低,每层的单元测试就越容易。