mikehaertl\pdftk\Pdf::generateFdfFile PHP Method

    public function generateFdfFile($name)
    {
        $this->constrainSingleFile();
        $this->getCommand()->setOperation('generate_fdf');
        $this->_output = $name;
        return $this->execute();
    }

 public function testCanCreateFdfFileFromPdf()
 {
     $form = $this->getFilledForm();
     $file = __DIR__ . '/test.fdf';
     $pdf = new Pdf($form);
     $this->assertTrue($pdf->generateFdfFile($file));
     @unlink($file);
 }