Sonata\Exporter\Writer\CsvWriter::open PHP Method

    public function open()
    {
        $this->file = fopen($this->filename, 'w', false);
        if (true === $this->withBom) {
            fprintf($this->file, chr(0xef) . chr(0xbb) . chr(0xbf));
        }
    }

 public function testWithBom()
 {
     $writer = new CsvWriter($this->filename, ',', '"', '', true, true);
     $writer->open();
     $writer->write(array('name' => 'Rémi , ""2"', 'surname' => 'doe ', 'year' => '2001'));
     $writer->close();
     $expected = chr(0xef) . chr(0xbb) . chr(0xbf) . 'name,surname,year' . "\n" . '"Rémi , """"2""","doe ",2001';
     $this->assertEquals($expected, trim(file_get_contents($this->filename)));
 }