title: phpunit dbunit @dataProvider doesn't work
body: <p>I spent a lot of time by searching where is the problem, but i haven't find anything.</p>
  
  <p>It sais "testAdd caused an ERROR: Missing argument". Simply the dataProvider isn't executed, when I run the test. I tried to put die() into the dataProvider and it hasn't died.</p>
  
  <p>This is my code:</p>
  
  <pre><code>class LabelEntityModelTest extends PHPUnit_Extensions_Database_TestCase
  {
  
      private static $connection = NULL;
  
      /**
       * @var \CXNS\DB\Connections\Connection
       */
      private static $appConnection;
      private static $table;
  
      public function __construct()
      {
          if (self::$connection) {
              return;
          }
  
          $pdo = new \PDO($GLOBALS['DB_DSN'], $GLOBALS['DB_USER'], $GLOBALS['DB_PASSWD']);
          self::$appConnection = new \CXNS\DB\Connections\Connection(array("prefix" =&gt; "test_", "driver" =&gt; "pdo", "resource" =&gt; $pdo));
          self::$appConnection-&gt;connect();
  
          self::$connection = $this-&gt;createDefaultDBConnection($pdo, 'mysql');
  
          self::$table = $this-&gt;createXMLDataSet(__DIR__ . '/fixtures/tables.xml');
      }
  
      protected function getDataSet()
      {
          return self::$table;
      }
  
      public function getConnection()
      {
          return self::$connection;
      }
  
      public function getAppConnection()
      {
          return self::$appConnection;
      }
  
      /**
       * @group onlyThis
       * @dataProvider providerAdd
       */
      public function testAdd($labelId, $entityId)
      {
          $lem = new \appLibs\Labels\LabelEntityModel($this-&gt;getAppConnection(), "contacts");
  
          $lem-&gt;add($labelId, $entityId);
  
          $count = $this-&gt;getAppConnection()
              -&gt;select("id")
              -&gt;from("label_relationships")
              -&gt;where("label_id = %i", $labelId)
              -&gt;where("table_ref_id = %i", $entityId)
              -&gt;count();
  
          $this-&gt;assertEquals(1, $count, "insert failed");
      }
  
      public function providerAdd()
      {
          return array(
              array(2, 3),
              array(3, 4),
              array(3, 4),
              array(3, 4),
              array(3, 4),
              array(3, 4),
              array(5, 7)
          );
      }
  }
  </code></pre>
  
  <p>Thank you for your help.</p>