Unit Test a file upload, how?

Question

Using MVC3.NET I have a file upload method in a controller that works fine with the following signature public ActionResult UploadFile(IEnumerable<HttpPostedFileBase> file)

How can I unit test this with NUnit? I have looked around and everyone seems to point to Moq but I'm new to unit testing and cannot get Moq working.

I have found interesting blogs such as this: http://danielglyde.blogspot.com/2011/07/tdd-with-aspnet-mvc-3-moq-and.html but am struggling to figure out how the same might be done to 'fake' a file upload, and am also wary that a lot on moq examples that I have managed to find now seem to have deprecated code in them.

I would simply like to know how I can simulate a HttpPostedFileBase so I can test my upload code, using Moq or otherwise - I would be really grateful if someone could give me some code examples on how to do this.

The following code taken from other examples on here:

var file = new Mock<HttpPostedFileBase>();
            file.Setup(f => f.ContentLength).Returns(1);
            file.Setup(f => f.FileName).Returns("test.txt");

controller.upload(file);

generates the following error when I try to compile:

cannot convert from 'Moq.Mock' to 'System.Web.HttpPostedFileBase'

I have changed the method to take a singular HttpPostedFileBase for now, rather than an IEnumerable, as being able to 'mock' one is what I'm trying to focus on for the purpose of this question.

See the question http://stackoverflow.com/questions/5515404/how-to-unit-test-asp-net-mvc-fileupload — wnascimento, Nov 29 '11 at 10:13
I want to be able to pass an object into the method from my test method that will allow me to test the code inside it, so I want to do this from a test method: controller.UploadFile(fakeObjectHereButDontKnowHow). The Chris Sainty example contains a lot of obsolete code, I think. As I said I have struggled with the some of the online material for moq.. — DevDave, Nov 29 '11 at 10:17

score 25 · Accepted Answer · answered Nov 29 '11 at 10:22

Assuming a standard file upload action:

[HttpPost]
public ActionResult UploadFile(IEnumerable<HttpPostedFileBase> files)
{
    foreach (var file in files)
    {
        var filename = Path.Combine(Server.MapPath("~/app_data"), file.FileName);
        file.SaveAs(filename);
    }
    return View();
}

you could test it like this:

[Test]
public void Upload_Action_Should_Store_Files_In_The_App_Data_Folder()
{
    // arrange
    var httpContextMock = new Mock<HttpContextBase>();
    var serverMock = new Mock<HttpServerUtilityBase>();
    serverMock.Setup(x => x.MapPath("~/app_data")).Returns(@"c:\work\app_data");
    httpContextMock.Setup(x => x.Server).Returns(serverMock.Object);
    var sut = new HomeController();
    sut.ControllerContext = new ControllerContext(httpContextMock.Object, new RouteData(), sut);

    var file1Mock = new Mock<HttpPostedFileBase>();
    file1Mock.Setup(x => x.FileName).Returns("file1.pdf");
    var file2Mock = new Mock<HttpPostedFileBase>();
    file2Mock.Setup(x => x.FileName).Returns("file2.doc");
    var files = new[] { file1Mock.Object, file2Mock.Object };

    // act
    var actual = sut.UploadFile(files);

    // assert
    file1Mock.Verify(x => x.SaveAs(@"c:\work\app_data\file1.pdf"));
    file2Mock.Verify(x => x.SaveAs(@"c:\work\app_data\file2.doc"));
}

Obviously all the HttpContext setup part should be externalized into a reusable class that could be called in the [SetUp] phase of your unit test to prepare the mock context of the subject under test and to avoid repeating it in every single unit test.

Unit Test a file upload, how?

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