Pop\File\File::append PHP Method

    public function append($data)
    {
        return $this->write($data, true);
    }

 public function testAppend()
 {
     $f = new File(__DIR__ . '/../tmp/access.txt');
     $f->append('123456');
     $f->append('789');
     $this->assertContains('123456789', $f->read());
 }