如何使用VirtualPathUtility.GetAbsolute方法在单元测试代码时模拟上下文

Question

我正在对使用VirtualParthUtility.GetAbsolute的代码运行单元测试,但是在模拟上下文时遇到了问题.

我已经用Moq设置了一个模拟上下文,如下所示

    private Mock<HttpContextBase> MakeMockHttpContext(string url) // url = "~/"
    {
        var mockHttpContext = new Mock<HttpContextBase>();

        // Mock the request
        var mockRequest = new Mock<HttpRequestBase>();
        mockRequest.Setup(x => x.ApplicationPath).Returns("/");
        mockRequest.Setup(x => x.Path).Returns("/");
        mockRequest.Setup(x => x.PathInfo).Returns(string.Empty);
        mockRequest.Setup(x => x.AppRelativeCurrentExecutionFilePath).Returns(url);

        mockHttpContext.Setup(x => x.Request).Returns(mockRequest.Object);

        // Mock the response
        var mockResponse = new Mock<HttpResponseBase>();
        mockResponse.Setup(x => x.ApplyAppPathModifier(It.IsAny<string>())).Returns((string s) => s);

        mockHttpContext.Setup(x => x.Response).Returns(mockResponse.Object);

        return mockHttpContext;
    }

并将其附加到MVC控制器

_myController.ControllerContext = new ControllerContext(MakeMockHttpContext("~/").Object, new RouteData(), _slideSelectorController);

测试期间运行的代码命中行:

venue.StyleSheetUrl = VirtualPathUtility.ToAbsolute(venue.StyleSheetUrl); // input like "~/styles/screen.css"

每次运行时,它都会进入System.Web.VirtualPathUtility,问题是返回的"VirtualParthString"总是抛出异常:

 public static string ToAbsolute(string virtualPath)
{
  return VirtualPath.CreateNonRelative(virtualPath).VirtualPathString;
}

在System.Web.VirtualPathString中很容易看到异常的原因:

    public string VirtualPathString
{
  get
  {
    if (this._virtualPath == null)
    {
      if (HttpRuntime.AppDomainAppVirtualPathObject == null)
      {
        throw new HttpException(System.Web.SR.GetString("VirtualPath_CantMakeAppAbsolute", new object[] { this._appRelativeVirtualPath }));
      }
      if (this._appRelativeVirtualPath.Length == 1)
      {
        this._virtualPath = HttpRuntime.AppDomainAppVirtualPath;
      }
      else
      {
        this._virtualPath = HttpRuntime.AppDomainAppVirtualPathString + this._appRelativeVirtualPath.Substring(2);
      }
    }
    return this._virtualPath;
  }
}

通过Watch Window,我可以看到_virtualPath和HttpRuntime.AppDomainAppVirtualPathString都是null,因此它会抛出异常.

如果设置了_virtualPath,则不会发生异常.但是,在VirtualPath.Create方法创建了新的VirtualPath对象之后,它不会在返回之前设置_virtualPath属性.到目前为止,Create方法的摘录是:

VirtualPath path = new VirtualPath();
  if (UrlPath.IsAppRelativePath(virtualPath))
  {
    virtualPath = UrlPath.ReduceVirtualPath(virtualPath);
    if (virtualPath[0] == '~')
    {
      if ((options & VirtualPathOptions.AllowAppRelativePath) == 0)
      {
        throw new ArgumentException(System.Web.SR.GetString("VirtualPath_AllowAppRelativePath", new object[] { virtualPath }));
      }
      path._appRelativeVirtualPath = virtualPath;
      return path;

因此,如果有人可以建议如何让这个单元测试工作,这将是非常有帮助的!

谢谢,

史蒂夫

Answer 1

我只想创建一个包装器接口.就像是:

public interface IPathUtilities
{
    string ToAbsolute(string virtualPath);
}

您可以将其注入控制器.在测试时,使用存根.在运行时,您将拥有一个实现IPathUtilities和调用的类VirtualPathUtility.ToAbsolute().