Can not instantiate proxy...Could not find a parameterless constructor

I am trying to create a unit test using Moq which tests the MongoDB.AspNet.Identity V2 provider. This line is giving me grief:

var appUser = new Mock<PreRegistrationMVC.Models.ApplicationUser>();
var userStore = new Mock<MongoDB.AspNet.Identity.UserStore<PreRegistrationMVC.Models.ApplicationUser>>();

It seems the userStore won't instantiate properly here is the error.

Castle.DynamicProxy.InvalidProxyConstructorArgumentsException was unhandled by user code
  HResult=-2147024809
  Message=Can not instantiate proxy of class: MongoDB.AspNet.Identity.UserStore`1[[MVC.Models.ApplicationUser, MVC, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].
Could not find a parameterless constructor.
  Source=Moq
  StackTrace:
       at Castle.DynamicProxy.ProxyGenerator.CreateClassProxyInstance(Type proxyType, List`1 proxyArguments, Type classToProxy, Object[] constructorArguments)
       at Castle.DynamicProxy.ProxyGenerator.CreateClassProxy(Type classToProxy, Type[] additionalInterfacesToProxy, ProxyGenerationOptions options, Object[] constructorArguments, IInterceptor[] interceptors)
       at Moq.Proxy.CastleProxyFactory.CreateProxy(Type mockType, ICallInterceptor interceptor, Type[] interfaces, Object[] arguments)
       at Moq.Mock`1.<InitializeInstance>b__2()
       at Moq.PexProtector.Invoke(Action action)
       at Moq.Mock`1.InitializeInstance()
       at Moq.Mock`1.OnGetObject()
       at Moq.Mock.GetObject()
       at Moq.Mock.get_Object()
       at Moq.Mock`1.get_Object()
       at MVC_Tests.Identity.Accounts.AccountController_Test.TestSuccessfulRegister() in c:\Users\Tim\Documents\Visual Studio 2013\Projects\PreRegistrationApp\MVC_Tests\Identity\Accounts\AccountController_Test.cs:line 108
  InnerException: 

I am completely new to Moq so I am looking for: What type of settings are needed for Moq to instantiate this? Is there something about the UserStore class that won't play well with Moq?

Thanks for reading.

MOQ is good for mocking interfaces, but does not work so well with concrete classes. So instead of mocking concrete class, ask for the inteface:

var userStore = new Mock<IUserStore<PreRegistrationMVC.Models.ApplicationUser>>();

Also ApplicationUser should be POCO, so no need to mock it, just create its instance without MOQ and use in tests.

You can try referring Mock behavior,as shown below

Mock<testClass>(MockBehavior.Strict, new object[] {"Hello"}); 

I had this problem. I had written...

var x = new Mock<Concrete>();

... instead of ...

var x = new Mock<IConcrete>();

I know this is a late response, but I was looking for an answer and couldn't find exactly what I needed, but when creating a mock, you can pass the parameters to your wanted constructor.

So for example if you have class like this:

public class Foo
{
    private readonly Boo _boo;

    public Foo(Boo boo)
    {
        _boo = boo;
    }
}

You can mock it like this:

private readonly Mock<Foo> _foo = new Mock<Foo>(new Mock<Boo>().Object);