Mutagenesis\Mutation\OperatorIncrement::getMutation PHP Метод

    public function getMutation(array $tokens, $index)
    {
        $tokens[$index][0] = T_DEC;
        $tokens[$index][1] = '--';
        return $tokens;
    }

 public function testReturnsTokenEquivalentToDecrementOperator()
 {
     $mutation = new OperatorIncrement(10);
     $this->assertEquals(array(10 => array(T_DEC, '--')), $mutation->getMutation(array(), 10));
 }