title: Codeception unit tests - error Class 'Dog' not found
body: <p>I'm using Codeception to TDD the development of a simple application in PHP. I've created my first unit test called DogTest.php with a simple assertion, but it's complaining about not being able to find the Dog class.</p>
  
  <p>I have created a Dog.php file in the root directory, and also placed it under /src, but neither is working. I think this is either a namespace issue or an autoloader issue, but the Codeception documents (and the various TDD guides I've looked at) have this important detail missing.</p>
  
  <p>Can someone please advise on how to get my DogTest to detect the Dog class?</p>