> We all do this, by default, don't we?

manually yes, not generated.

Szabgab only hinted about tests that handle code like $a+ switched to $a-

so in the following case

 
sub foo { 
   my ($a,$b) = @_;
   return $a + $b;
}

[download]

testing foo(*,0) (with * any number) will always pass, even if you change + to -

If several pairs of values were generated by a random generator and the result was approved manually, then the likelyhood of a false positive would be minimal.

And new test input could be generated quickly, depending on the manual decision if the code change was really intended or just a bug.

As I said to (semi-) automatize this one needed to parse already a lot of the functions body.

Anyway I don't want to elaborate more, without further explanation by the OP. (the requirements sound paradoxial)

Cheers Rolf
(addicted to the Perl Programming Language and ☆☆☆☆ :)
Je suis Charlie!

In reply to Re^3: Testing my tests by LanX
in thread Testing my tests (mutation testing) by szabgab

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