title: Symfony LiipFunctionalTestBundle loadFixtures duplicate entry
body: <p>I'm struggling again with the Liip/LiipFunctionalTestBundle in Symfony v2.7. I have two tests, which do nothing but load fixtures via this bundle. If I load the same fixture class in both classes, the second one tries to commit his fixtures twice! If the fixtures are different, everything is fine.</p>
  
  <p>Does someone have experience with this bundle? </p>
  
  <pre><code>use Liip\FunctionalTestBundle\Test\WebTestCase as WebTestCase;
  
  class AgencyControllerTest extends WebTestCase
  {    
      public function testOne()
      {
          $this-&gt;loadFixtures([
              'Barra\AdminBundle\DataFixtures\ORM\LoadUserData',
          ]);
      }
  
      public function testTwo()
      {
          $this-&gt;loadFixtures([
              'Barra\AdminBundle\DataFixtures\ORM\LoadUserData',
              'Barra\AdminBundle\DataFixtures\ORM\LoadAgencyData',
          ]);
      }
  </code></pre>
  
  <p>test.log extract</p>
  
  <pre><code>doctrine.DEBUG: DELETE FROM Agency [] []
  doctrine.DEBUG: DELETE FROM AppUser [] []
  [...]
  doctrine.DEBUG: "START TRANSACTION" [] []
  doctrine.DEBUG: INSERT INTO AppUser (...) {..1..} []
  doctrine.DEBUG: INSERT INTO AppUser (...) {..2..} []
  doctrine.DEBUG: INSERT INTO AppUser (...) {..3..} []
  doctrine.DEBUG: "COMMIT" [] []
  
  doctrine.DEBUG: DELETE FROM Agency [] []
  doctrine.DEBUG: DELETE FROM AppUser [] []
  [...]
  doctrine.DEBUG: "START TRANSACTION" [] []
  doctrine.DEBUG: INSERT INTO Agency (...) {..1..} []
  doctrine.DEBUG: INSERT INTO Agency (...) {..2..} []
  doctrine.DEBUG: INSERT INTO Agency (...) {..3..} []
  doctrine.DEBUG: INSERT INTO AppUser (...) {..1..} []
  doctrine.DEBUG: INSERT INTO AppUser (...) {..2..} []
  doctrine.DEBUG: INSERT INTO AppUser (...) {..3..} []
  doctrine.DEBUG: INSERT INTO AppUser (...) {..1..} [] &lt;---
  [2015-10-25 11:39:09] doctrine.DEBUG: "ROLLBACK" [] []
  
  SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '1' for key 'UNIQ_8105EAD692FC23A8'
  </code></pre>