/**
  * tests computation of a records differences described by a set of modification logs
  */
 public function testComputeDiff()
 {
     $diffs = $this->_modLogClass->computeDiff($this->_persistantLogEntries)->toArray();
     $this->assertEquals(2, count($diffs));
     // we changed two attributes
     foreach ($diffs as $diff) {
         switch ($diff['modified_attribute']) {
             case 'FirstTestAttribute':
                 $this->assertEquals('Hamburg', $diff['old_value']);
                 $this->assertEquals('Stuttgart', $diff['new_value']);
                 break;
             case 'SecondTestAttribute':
                 $this->assertEquals('Deutschland', $diff['old_value']);
                 $this->assertEquals('Italien', $diff['new_value']);
         }
     }
 }