title: Rails not loading fixtures in test with similar names with STI
body: <p>I have 3 classes with STI and I want to load fixtures for each:</p>
  
  <p><code>Employee</code></p>
  
  <p><code>Admin &lt; Employee</code></p>
  
  <p><code>OtherEmployee &lt; Employee</code></p>
  
  <p>My test_helper files has <code>fixtures :all</code></p>
  
  <p>and the fixtures are in:</p>
  
  <p><code>employees.yml</code>
  <code>admins.yml</code>
  <code>other_employees.yml</code></p>
  
  <p>and yet only the data from <code>other_employees.yml</code> is loaded into the database. Any idea why or how to fix this? </p>
  
  <p>Fixtures: </p>
  
  <pre><code>#employees.yml
  one: 
    id: 1
    name: Name1
    full_name: FName1
    type: Admin
  
  two: 
    name: Name2
    full_name: FName2
    type: Admin
  
  three:
    name: Name3
    full_name: FName3
    type: OtherEmployee
  
  #admins.yml
  
  adminone:
     name: Admin1
     full_name: FAdmin1
     type: Admin
  
  admintwo:
     name: Admin2
     full_name: FAdmin2
     type: Admin
  
  #other_employees.yml
  
  oeone:
     name: Oemp1
     full_name: FOemp1
     type: OtherEmployee
  
  oetwo:
     name: Oemp2
     full_name: FOemp2
     type: OtherEmployee
  </code></pre>