问题描述

我正在使用本教程来伪造我的dbcontext和测试: http://refactorthis.wordpress.com/2011/05/31/mock-faking-dbcontext-in-entity-framework-4-1-带 – a-generic-repository/

但我必须更改fakemainmodulecontext的实现以在我的控制器中使用:

public class FakeQuestiona2011Context : IQuestiona2011Context
{
    private IDbSet<Credencial> _credencial;
    private IDbSet<Perfil> _perfil;
    private IDbSet<Apurador> _apurador;
    private IDbSet<Entrevistado> _entrevistado;
    private IDbSet<Setor> _setor;
    private IDbSet<Secretaria> _secretaria;
    private IDbSet<Pesquisa> _pesquisa;
    private IDbSet<Pergunta> _pergunta;
    private IDbSet<Resposta> _resposta;

    public IDbSet<Credencial> Credencial { get { return _credencial ?? (_credencial = new FakeDbSet<Credencial>()); } set { } }
    public IDbSet<Perfil> Perfil { get { return _perfil ?? (_perfil = new FakeDbSet<Perfil>()); } set { } }
    public IDbSet<Apurador> Apurador { get { return _apurador ?? (_apurador = new FakeDbSet<Apurador>()); } set { } }
    public IDbSet<Entrevistado> Entrevistado { get { return _entrevistado ?? (_entrevistado = new FakeDbSet<Entrevistado>()); } set { } }
    public IDbSet<Setor> Setor { get { return _setor ?? (_setor = new FakeDbSet<Setor>()); } set { } }
    public IDbSet<Secretaria> Secretaria { get { return _secretaria ?? (_secretaria = new FakeDbSet<Secretaria>()); } set { } }
    public IDbSet<Pesquisa> Pesquisa { get { return _pesquisa ?? (_pesquisa = new FakeDbSet<Pesquisa>()); } set { } }
    public IDbSet<Pergunta> Pergunta { get { return _pergunta ?? (_pergunta = new FakeDbSet<Pergunta>()); } set { } }
    public IDbSet<Resposta> Resposta { get { return _resposta ?? (_resposta = new FakeDbSet<Resposta>()); } set { } }

    public void SaveChanges()
    {
        // do nothing (probably set a variable as saved for testing)
    }
}

和我的测试:

[TestMethod]
public void IndexTest()
{
    IQuestiona2011Context fakeContext = new FakeQuestiona2011Context();
    var mockAuthenticationService = new Mock<IAuthenticationService>();

    var apuradores = new List<Apurador>
    {
        new Apurador() { Matricula = "1234", Nome = "Acaz Souza Pereira", Email = "acaz@telecom.inf.br", Ramal = "1234" },
        new Apurador() { Matricula = "4321", Nome = "Samla Souza Pereira", Email = "samla@telecom.inf.br", Ramal = "4321" },
        new Apurador() { Matricula = "4213", Nome = "Valderli Souza Pereira", Email = "valderli@telecom.inf.br", Ramal = "4213" }
    };
    apuradores.ForEach(apurador => fakeContext.Apurador.Add(apurador));

    ApuradorController apuradorController = new ApuradorController(fakeContext, mockAuthenticationService.Object);
    ActionResult actionResult = apuradorController.Index();

    Assert.IsNotNull(actionResult);
    Assert.IsInstanceOfType(actionResult, typeof(ViewResult));

    ViewResult viewResult = (ViewResult)actionResult;

    Assert.IsInstanceOfType(viewResult.ViewData.Model, typeof(IndexViewModel));

    IndexViewModel indexViewModel = (IndexViewModel)viewResult.ViewData.Model;

    Assert.AreEqual(3, indexViewModel.Apuradores.Count);
}

我正在做对吗?

不幸的是，你不是正确的，因为这篇文章是错误的.它假装FakeContext将使您的代码单元可测试，但它不会.一旦您将IDbSet或IQueryable曝光到您的控制器并且您将集合带到内存集合中，您就无法确定您的单元测试真正测试代码.在控制器中编写LINQ查询非常容易，它将通过您的单元测试(因为FakeContext使用LINQ-Objects)但在运行时失败(因为您的真实上下文使用LINQ-ENTITES).这使得您的单位测试无用的全部目的.

我的意见:如果要将设置暴露给Controller，请不要打扰伪装语境.而是使用具有真实数据库进行测试的集成测试.这是如何验证控制器中定义的LINQ查询的唯一方法，请执行您所期望的内容.

肯定，如果您想在您的集合中拨打ToList或FirstOrDefault，则为FakeContext将适合您，但一旦您做得更复杂，您可以很快找到一个陷阱(只需将字符串“不能被翻译成商店表达式”进入谷歌 – 只有在运行linq到实体时才会出现所有这些问题，但它们会将测试与linq-to-objects传递).

这是一个非常常见的问题，以便您可以查看其他示例:

<connectionStrings>
    <add name="MyDbContext"
       connectionString="Data Source=|DataDirectory|MyDb.sdf"
         providerName="System.Data.SqlServerCe.4.0"
         />
</connectionStrings>

Database.SetInitializer<MyDbContext>(new DropCreateDatabaseAlways<MyDbContext>());

public void Setup() {
    Database.SetInitializer<MyDbContext>(new DropCreateDatabaseAlways<MyDbContext>());
    context = new MyDbContext();
    context.Database.Initialize(force: true);
}