PHPUnit and C.R.A.P index

Question

I am using php undercontrol and the code browser report some CRAP index error on every setter/getter i.e. code like this

public function getFoo()
{
    return $this->_foo;
}

The getter/setter are covered by the unit testing, the complexity is none since there is no if/for/switch/foreach. so why I get a CRAP index of 1 for that code???

PS: self answering myself might be because the complexity is none but my main issue is that every getter/setter generate a warning because of the CRAP index so is there anyway to tell phpunit/php code coverage to make the CRAP equals to 0 for function with a 0 complexity index.

Answer 1

The minimum CRAP score is 1, not 0. This is because the algorithm for CRAP is

CRAP(m) = comp(m)^2 * (1 – cov(m)/100)^3 + comp(m)

and the minimum cyclomatic complexity (comp) value for a function is one. So the problem is not in phpunit, but whatever is flagging a CRAP of 1 as a problem.

In general, you want to set your CRAP threshold somewhere around 5, anywhere lower and you may as well just use a simple code coverage metric (and shoot for 100%) since the complexity factor barely weighs in. A CRAP of >= 30 means that no amount of testing can make your method not crappy.

Cyclomatic complexity can generally (but there is more than one definition) be hand calculated as:

• add 1 point for the function call
• add 1 point for every loop
• add 1 point for every branch