模拟对象无法返回所需的对象

Question

肯定会有一些我忽视的东西 - 通常是我遇到这样的问题.

我有一个控制器只是根据提供的ID返回一篇新闻文章:

[HandleError]
public class HomeController : Controller
{
    private readonly IArticleRepository articleRepository;

    public HomeController(IArticleRepository Repository)
    {
        articleRepository = Repository;
    }

    public ActionResult Index()
    {
        return View("Index");
    }

    // Here's the bit we're interested in
    public ActionResult Article(int id)
    {
        var article = articleRepository.GetById(id);

        return View("Article", article);
    }

}

我正在使用Moq嘲笑这个:

[TestFixture]
public class HomeControllerTests
{
    HomeController controller;
    int articleId;
    Article model;

    [TestFixtureSetUp]
    public void SetupMethods()
    {
        Mock<IArticleRepository> repositoryMock = new Mock<IArticleRepository>();
        repositoryMock.Setup(x => x.GetById(articleId)).Returns(GetSampleArticle());

        controller = new HomeController(repositoryMock.Object);
    }

    [Test]
    public void Article_Action_Returns_Requested_Article()
    {
        // Arrange
        model = new Article();
        articleId = 1;

        // Act
        ActionResult result = controller.Article(articleId);

        // Assert
        var viewResult = ((ViewResult)result);
        var returnedModel = viewResult.Model;
        Assert.IsInstanceOf<Article>(viewResult.Model);
        //Assert.AreEqual(articleId, returnedModel.ID);
    }
}

上面讨论的"GetSampleArticle"方法看起来像这样:

    private Article GetSampleArticle()
    {
        Article article = new Article()
        {
            Archived = false,
            Body = "<p>This is a dummy sample article for use in our mocks.</p>",
            EndDate = DateTime.Today.AddDays(30),
            ID = 1,
            Priority = 3,
            StartDate = DateTime.Today,
            Title = "Sample Article"
        };

        return article;
    }

但是我仍然为模型得到一个null类型.那么我忘记了什么？

News.Tests.Controllers.HomeControllerTests.Article_Action_Returns_Requested_Article:
  Expected: instance of <News.Data.Article>
  But was:  null

Answer 1

另一个想法是使用It.IsAny()方法来避免必须查找硬编码值:

repositoryMock.Setup(x => x.GetById(It.IsAny<int>())).Returns(GetSampleArticle());

这是安全的,因为你不关心articleId的实际价值,而不是它的检索机制.