Nancy.Testing exception thrown when testing POST route with Json content - nancy

Question

I'm attempting to write tests for my Nancy module, and it's not going too well so far.
Attempting to test two separate actions, one GET which is working just fine and a POST with application/json content in the request.
I'm slightly stabbing in the dark as to how the test for the POST should be written, but have come up with the following:
using NUnit.Framework;
[TestFixture]
public class MyModuleTests
{
Browser browser;
[SetUp]
public void SetUp()
{
browser = new Browser(with =>
{
with.Module<MyModule>();
with.EnableAutoRegistration();
});
}
[Test]
public void Can_Get_View()
{
// When
var result = browser.Get("/View", with => with.HttpRequest());
// Then
Assert.AreEqual(HttpStatusCode.OK, result.StatusCode); // this works
}
[Test]
public void Can_Post_to_EvaluateDocument()
{
var testData = new List<FakeInputValue>(){new FakeInputValue()
{
Name = "a",
Value = 0.35
}};
// When
var result = browser.Post("/Evaluate", with => //the exception is thrown on this line
{
with.HttpRequest();
with.JsonBody<IList<FakeInputValue>>(testData);
});
// Then
Assert.AreEqual(HttpStatusCode.OK, result.StatusCode);
}
}
class FakeInputValue
{
public string Name { get; set; }
public double Value { get; set; }
}
Unfortunately this throws the following juicy error
1) Test Error : MyModuleTests.Can_Post_to_EvaluateDocument
System.Exception : ConfigurableBootstrapper Exception
----> Nancy.RequestExecutionException : Oh noes!
----> System.Reflection.TargetInvocationException : Exception has been thrown by the target of an invocation.
----> System.MissingMethodException : No parameterless constructor defined for this object.
at Nancy.Testing.PassThroughStatusCodeHandler.Handle(HttpStatusCode statusCode, NancyContext context)
at Nancy.NancyEngine.CheckStatusCodeHandler(NancyContext context)
at Nancy.NancyEngine.<>c__DisplayClass8.<HandleRequestInternal>b__6(Task`1 completeTask)
at Nancy.NancyEngine.HandleRequestInternal(Request request, Func`2 preRequest)
at Nancy.NancyEngine.HandleRequest(Request request, Func`2 preRequest)
at Nancy.Testing.Browser.HandleRequest(String method, String path, Action`1 browserContext)
at MyModuleTests.Can_Post_to_EvaluateDocument() in line 49
--RequestExecutionException
at Nancy.NancyEngine.InvokeOnErrorHook(NancyContext context, ErrorPipeline pipeline, Exception ex)
--TargetInvocationException
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at Nancy.ModelBinding.DefaultBodyDeserializers.JsonBodyDeserializer.Deserialize(String contentType, Stream bodyStream, BindingContext context)
at Nancy.ModelBinding.DefaultBinder.Bind(NancyContext context, Type modelType, Object instance, BindingConfig configuration, String[] blackList)
at Nancy.ModelBinding.DynamicModelBinderAdapter.TryConvert(ConvertBinder binder, Object& result)
at CallSite.Target(Closure , CallSite , Object )
at System.Dynamic.UpdateDelegates.UpdateAndExecute1[T0,TRet](CallSite site, T0 arg0)
at MyModule.<.ctor>b__9(Object parameters)
at CallSite.Target(Closure , CallSite , Func`2 , Object )
at Nancy.Routing.Route.<>c__DisplayClass4.<Wrap>b__3(Object parameters, CancellationToken context)
--MissingMethodException
at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck)
at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark)
at System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark)
at System.Activator.CreateInstance(Type type, Boolean nonPublic)
at Nancy.Json.JavaScriptSerializer.ConvertToObject(IDictionary`2 dict, Type type)
at Nancy.Json.JavaScriptSerializer.ConvertToList(ArrayList col, Type type)
at Nancy.Json.JavaScriptSerializer.ConvertToType[T](Object obj)
Any help as to (a) how I might better test POST routes with application/json content in Nancy or (b) resolve this particular error!
edit 1
My module is as follows:
public class MyModule : NancyModule
{
public MyModule()
{
Get["/View"] = parameters =>
{
return View["myView"];
};
Post["/Evaluate"] = parameters =>
{
this.inputs = this.Bind<List<InputValue>>();
var evaluator = new Evaluator(inputs);
return Response.AsJson<List<Evaluation>>(evaluator.Evaluate());
};
}
}

Answer 1

After a lot of debugging and frustrated outputting to Console, I've tracked down the cause of the bug. The issue was with the lack of public setters in my InputValue class.
The buggy class was written as so:
public class InputValue
{
private readonly string _name;
private readonly double _value;
public InputValue(string inputName, double inputValue)
{
this._name = inputName;
this._value = inputValue;
}
public string Name
{
get
{
return this._name;
}
}
public double Value
{
get
{
return this._value;
}
}
}
I resolved the issue quite simply by allowing the properties to be set, as so:
public class InputValue
{
public string Name
{
get;
set;
}
public double Value
{
get;
set;
}
}