title: NSManagedObject convenience init in XCTestCase (Swift 3)
body: <p>creating NSManagedObjects like this:</p>
  
  <pre><code>let eniyty = MyManagedObject(context: myContext)
  </code></pre>
  
  <p>works well in application, but fails in test with message:
  ... must have a valid NSEntityDescription.</p>
  
  <p>at other hand this one works well both in application and tests:</p>
  
  <pre><code>let eniyty = MyManagedObject(entity: entityDescription!, insertInto: myContext)
  </code></pre>
  
  <p>My entities settings:</p>
  
  <p><a href="https://i.stack.imgur.com/9JLs9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/9JLs9.png" alt=""></a></p>
  
  <p>Any ideas? thanks</p>