function testBrr()
{
$str = 'a+(b+(c+1))';
$brr = new Brr();
$substituted = $brr->sub($str);
$this->assertEqual($substituted, 'a+([0]b+([1]c+1)[1])[0]');
$substituted = str_replace('a', 'A', $substituted);
$substituted = str_replace('b', 'B', $substituted);
$substituted = str_replace('c', 'C', $substituted);
$substituted = $brr->subback($substituted);
$this->assertEqual($substituted, 'A+(B+(C+1))');
}
