Testando upload de imagens no asp.net MVC

upload_mvc_.cs

[Test]
public void salva_imagem_quando_é_postada()
{
    var controller = new SomeController();
    var memoryStream = new MemoryStream();
    //resource file    
    ArquivosPostados.ImagemPostada.Save(memoryStream, ImageFormat.Jpeg);
    
    var postedFile = new Mock<HttpPostedFileBase>();
    postedFile.Setup(p => p.InputStream).Returns(memoryStream);
    
    var files = new Mock<HttpFileCollectionBase>();
    files.Setup(f => f[0]).Returns(postedFile.Object);
    
    var request = new Mock<HttpRequestBase>();
    request.Setup(r => r.Files).Returns(files.Object);
    
    var context = new Mock<HttpContextBase>();
    context.Setup(c => c.Request).Returns(request.Object);
    
    var controllerContext = new ControllerContext(context.Object, new RouteData(), controller);
    controller.ControllerContext = controllerContext;
    
    //Act    
    var response = controller.UploadImage();
    //Assert    
    postedFile.Verify(p => p.SaveAs(It.IsAny<string>()), Times.Once());
}