We wanted to upgrade our projects from ASP.NET MVC 2 to 3. Most of our tests succeeded, but there are some that fail on ValueProviderFactories.Factories.GetValueProvider(context)
.
Here is a simple test class that ilustrates the problem.
[TestFixture]
public class FailingTest
{
[Test]
public void Test()
{
var type = typeof(string);
// any controller
AuthenticationController c = new AuthenticationController();
var httpContext = new Mock<HttpContextBase>();
var context = c.ControllerContext = new ControllerContext(httpContext.Object, new RouteData(), c);
IModelBinder converter = ModelBinders.Binders.GetBinder(type);
var bc = new ModelBindingContext
{
ModelName = "testparam",
ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(null, type),
ValueProvider = ValueProviderFactories.Factories.GetValueProvider(context)
};
Console.WriteLine(converter.BindModel(context, bc));
}
}
Exception "Object reference not set to an instance of an object." is thrown when ValueProviderFactories.Factories.GetValueProvider(context)
is called. The stacktrace looks like this:
Microsoft.Web.Infrastructure.dll!Microsoft.Web.Infrastructure.DynamicValidationHelper.ValidationUtility.CollectionReplacer.GetUnvalidatedCollections(System.Web.HttpContext context) + 0x23 bytes
Microsoft.Web.Infrastructure.dll!Microsoft.Web.Infrastructure.DynamicValidationHelper.ValidationUtility.GetUnvalidatedCollections(System.Web.HttpContext context, out System.Collections.Specialized.NameValueCollection form, out System.Collections.Specialized.NameValueCollection queryString, out System.Collections.Specialized.NameValueCollection headers, out System.Web.HttpCookieCollection cookies) + 0xbe bytes
System.Web.WebPages.dll!System.Web.Helpers.Validation.Unvalidated(System.Web.HttpRequest request) + 0x73 bytes
System.Web.WebPages.dll!System.Web.Helpers.Validation.Unvalidated(System.Web.HttpRequestBase request) + 0x25 bytes
System.Web.Mvc.DLL!System.Web.Mvc.FormValueProviderFactory..ctor.AnonymousMethod__0(System.Web.Mvc.ControllerContext cc) + 0x5a bytes
System.Web.Mvc.DLL!System.Web.Mvc.FormValueProviderFactory.GetValueProvider(System.Web.Mvc.ControllerContext controllerContext) + 0xa0 bytes
System.Web.Mvc.DLL!System.Web.Mvc.ValueProviderFactoryCollection.GetValueProvider.AnonymousMethod__7(System.Web.Mvc.ValueProviderFactory factory) + 0x4a bytes
System.Core.dll!System.Linq.Enumerable.WhereSelectEnumerableIterator<System.Web.Mvc.ValueProviderFactory,<>f__AnonymousType2<System.Web.Mvc.ValueProviderFactory,System.Web.Mvc.IValueProvider>>.MoveNext() + 0x24d bytes
System.Core.dll!System.Linq.Enumerable.WhereSelectEnumerableIterator<<>f__AnonymousType2<System.Web.Mvc.ValueProviderFactory,System.Web.Mvc.IValueProvider>,System.Web.Mvc.IValueProvider>.MoveNext() + 0x2ba bytes
mscorlib.dll!System.Collections.Generic.List<System.Web.Mvc.IValueProvider>.List(System.Collections.Generic.IEnumerable<System.Web.Mvc.IValueProvider> collection) + 0x1d8 bytes
System.Core.dll!System.Linq.Enumerable.ToList<System.Web.Mvc.IValueProvider>(System.Collections.Generic.IEnumerable<System.Web.Mvc.IValueProvider> source) + 0xb5 bytes
System.Web.Mvc.DLL!System.Web.Mvc.ValueProviderFactoryCollection.GetValueProvider(System.Web.Mvc.ControllerContext controllerContext) + 0x24d bytes
test.DLL!FailingTest.Test() Line 31 + 0xf9 bytes C#
I wanted to know the reason why it throws the exception and saw:
public static ValidationUtility.UnvalidatedCollections GetUnvalidatedCollections(HttpContext context)
{
return (ValidationUtility.UnvalidatedCollections) context.Items[_unvalidatedCollectionsKey];
}
So, are we back in past when we were dependent on HttpContext.Current
? How to workaround it?
This can easily be solved by prox-ing ValueProviders that access HttpContext to a the one ignoring it.
I have explained everything in my blog post: Unit test actions with ValueProviderFactories in ASP.NET MVC3.
The key is this code:
public static class ValueProviderFactoresExtensions {
public static ValueProviderFactoryCollection ReplaceWith<TOriginal>(this ValueProviderFactoryCollection factories, Func<ControllerContext, NameValueCollection> sourceAccessor) {
var original = factories.FirstOrDefault(x => typeof(TOriginal) == x.GetType());
if (original != null) {
var index = factories.IndexOf(original);
factories[index] = new TestValueProviderFactory(sourceAccessor);
}
return factories;
}
class TestValueProviderFactory : ValueProviderFactory {
private readonly Func<ControllerContext, NameValueCollection> sourceAccessor;
public TestValueProviderFactory(Func<ControllerContext, NameValueCollection> sourceAccessor) {
this.sourceAccessor = sourceAccessor;
}
public override IValueProvider GetValueProvider(ControllerContext controllerContext) {
return new NameValueCollectionValueProvider(sourceAccessor(controllerContext), CultureInfo.CurrentCulture);
}
}
}
So it can be used as:
ValueProviderFactories.Factories
.ReplaceWith<FormValueProviderFactory>(ctx => ctx.HttpContext.Request.Form)
.ReplaceWith<QueryStringValueProviderFactory>(ctx => ctx.HttpContext.Request.QueryString);
It was actually very easy :)
UPDATE: As mentioned in comments you should remember to:
ctx.HttpContext.Request.ContentType
property to some not-null value, otherwise the JsonValueProviderFactory will throw exception. I prefer create a mock and set default value there.HttpFileCollectionValueProviderFactory
as it can be used during binding.If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With