[Pharo-project] Good reference on time on unit testing?

Steven Baker steven at stevenrbaker.com
Sun Feb 27 21:31:24 CET 2011


I never worry about "proving" it. When I've worked for clients who
have insisted that I leave the testing out because they don't want to
"pay extra" for the time spent, I simply don't push the tests to their

I test for myself, because I have a personal commitment to do the best
job possible.


On Sun, Feb 27, 2011 at 12:11 PM, Peter Hugosson-Miller
<oldmanlink at gmail.com> wrote:
> Steven, you're making perfect sense to me, and I think almost everyone here
> agrees with you.
> Bill's problem (if I've understood him correctly) is that he needs to
> convince some pointy-haired-boss-type person, by directing him or her to a
> well-respected "official" statistic that "proves" what we all know to be
> true from experience. Sadly, I think it will be hard to find it :-(
> --
> Cheers,
> Peter
> On Sun, Feb 27, 2011 at 9:04 PM, Steven Baker <steven at stevenrbaker.com>
> wrote:
>> I've always felt that "test driving" code actually results in negative
>> time spent on "testing". I spend (and everyone I know that tests well
>> does as well) a lot less time writing code test-first than I ever
>> would writing the same code without the tests first. Also, I spend far
>> less time (almost none) manually testing functionality. So TDD results
>> in net negative time difference.
>> (Apologize if I'm incoherent, the cold and flu drugs are strong in this
>> one.)
>> -Steven
>> On Sun, Feb 27, 2011 at 11:51 AM, Norbert Hartl <norbert at hartl.name>
>> wrote:
>> >
>> > On 27.02.2011, at 13:58, Schwab,Wilhelm K wrote:
>> >
>> >> Norbert,
>> >>
>> >> Excellent points - I take exception with only one: you assume that all
>> >> developers test - that is sadly not true.  I am involved with a group who
>> >> seem to think that a handful of tests added at the last minute will somehow
>> >> magically fix their problems.
>> >>
>> > It seems I wasn't clear on this one. I'm trying to making a point that
>> > there is no distinction between "testing" - "no testing" but between
>> > "testing" - "writing tests". If you take compilation you test the code for
>> > syntax and language quirks. If a developer runs the program he develops than
>> > he is testing already. Testing and running a program is the same form that
>> > point of view. He takes input parameter and expects output parameter. That
>> > is testing. The point is just that developers do it manually and that is not
>> > reproducable. So there is no real difference between manual testing all the
>> > time and written test case. Only that repeating the testing procedure is
>> > boring and therefor supposed to be done by a machine. So if developers could
>> > see that the just need to put the work they already doing into a test will
>> > ease the work without changing much. They are just changing style and save
>> > time. That's it. Talking about 100% test coverage and holistic views about
>> > what the perfect testing could be doesn't help.
>> >
>> >> I have no problem arguing that testing (if done well) can/will reduce
>> >> overall development time; the question is how much of that time one should
>> >> expect to devote to writing and maintaining unit and acceptance tests?
>> >>
>> > I understand your intention but the view is inapropriate. Coding and
>> > testing aren't two things. It is something that belongs together (if you
>> > changed coding style). So that's why it is hard to estimate a time that
>> > should be spent. To me it is more comparabale to this: We all know
>> > collections are great. Imagine someone asking you "Can anyone recommend a
>> > good reference on the amount of time one should expect to spend writing code
>> > that uses collections?". What would you say? There is no answer. That
>> > doesn't mean you can't solve the problem. But you won't solving it by saying
>> > "It is 38.345 % of the time". If people don't get it you have to convince
>> > and/or teach them. I had several times where I could show the developer that
>> > he is gaining time from doing it. That works. Everything else is targeted
>> > towards excel manipulators.
>> >
>> > Norbert
>> >
>> >
>> >> ________________________________________
>> >> From: pharo-project-bounces at lists.gforge.inria.fr
>> >> [pharo-project-bounces at lists.gforge.inria.fr] On Behalf Of Norbert Hartl
>> >> [norbert at hartl.name]
>> >> Sent: Sunday, February 27, 2011 5:41 AM
>> >> To: Pharo-project at lists.gforge.inria.fr
>> >> Subject: Re: [Pharo-project] Good reference on time on unit testing?
>> >>
>> >> Hi,
>> >>
>> >> On 27.02.2011, at 04:52, Schwab,Wilhelm K wrote:
>> >>
>> >>> Hello all,
>> >>>
>> >>> Can anyone recommend a good reference on the amount of time one should
>> >>> expect to spend writing tests?  I will have to be the messenger (will be
>> >>> wearing running shoes just in case...), but I want the message to come from
>> >>> a solid source.
>> >>
>> >> I find that really hard to answer. To me the problem is the question
>> >> itself. I heard the "..amount of time one should expect to spend writing
>> >> tests?" so often in companies and I think it was always exactly this phrase.
>> >> While the question is valid it gives the impression there is something that
>> >> decucts time from your "normal" development work. So the people that are
>> >> asking this question are often managing people that have read something
>> >> about code quality and they want to apply _this_ to their teams.
>> >> The definition over time is troublesome, too. Testing is not easy.
>> >> Everything you read about testing gives you the impression that everyone
>> >> knows how to test and that those developers are just too lazy. And that is
>> >> not true. Most developers I met had problems to see what testing is all
>> >> about. The don't see interfaces as provable promises etc. So if you tell any
>> >> of these developers they should spend 1 hour a day in testing than you will
>> >> get tests that are counter-productive. My favorite example is the one where
>> >> you have any composite object with an add method. Than the test goes like
>> >> adding something via the interface and then try to access the internal array
>> >> and check if it is of size 1. To me it is the same as with documentation. I
>> >> prefer to have less documentation than useless documentation.
>> >>
>> >> So every developer is testing in some way. You either test and debug on
>> >> the way in an unstructured form or you write tests. To me writing tests is
>> >> not an add-on it is a change in working style. From this point of view I
>> >> would state that the time I need to spend _additionally_ for testing is
>> >> negative.  I grew up with a print statement being the ultimate debugging
>> >> tool. A print/debugging statement is added at the time of debugging and
>> >> probably removed if the error seems to be fixed. That can lead to a
>> >> situation where you do this multiple times. Writing the same as a test (and
>> >> that forces you to produce more fine grained code) you will have a saving in
>> >> time and a little assurance about regression. Regression debugging
>> >> (debugging it again later) is much more time spent because you have to fix
>> >> the error _and_ you need to focus again on that problem (which takes most of
>> >> the time). So the point in writing tests is not to spend time but to save
>> >> time.
>> >>
>> >> The amount of time one should expect to spend writing tests is less
>> >> than the time you need to spend for testing otherwise. :)
>> >>
>> >> Norbert

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