title: Testing framework says entity has no key defined for built in entity
body: <pre><code>Castle.Proxies.IdentityUserLogin: : EntityType 'IdentityUserLogin' has no key defined. Define the key for this EntityType.  
  </code></pre>
  
  <p>I am trying to setup tests for my MVC 5.1 project which uses EntityFramework version 6.1, AspNet.Identity.Core version 2.0, AspNet.Identity.EntityFramework version 2.0. My only test case is very simple and it is erroring with the above error for 'IdentityUserLogin' and for Entity Type 'IdentityUserRole' as soon as I try to run. The problem is that as far as I understand there are keys defined for both of these entities! As they are provided by the framework. I can't see explicitly their description in my code first portion but in the database I can see they both have keys.   </p>
  
  <p>In my test project I'm using Microsoft.VisualStudio.TestTools.UnitTesting and Moq (as well as the EF &amp; Identity Core libs).  </p>
  
  <p>Any help or just pointing to resources would be much appreciated. I couldn't find anyone having a similar error. </p>