Doctrine\OXM\Storage\FileSystemStorage::setFileExtension PHP Method

    public function setFileExtension($fileExtension)
    {
        $this->fileExtension = $fileExtension;
    }

 /**
  * @test
  */
 public function itShouldSaveWithCustomExtension()
 {
     $this->fileSystem->setFileExtension('hobbes');
     $calvin = $this->_getClassMetadataMock('Calvin');
     $this->fileSystem->insert($calvin, 1, 'Spaceman Spiff');
     $this->assertTrue(is_file(__DIR__ . '/../Workspace/Calvin/1.hobbes'));
     $this->assertEquals('Spaceman Spiff', file_get_contents(__DIR__ . '/../Workspace/Calvin/1.hobbes'));
     @unlink(__DIR__ . '/../Workspace/Calvin/1.hobbes');
     @rmdir(__DIR__ . '/../Workspace/Calvin');
 }