TDD is dead. Long live testing.

Sat Sep 27 10:15:39 BRT 2014

Very interesting article from DHH, the rails creator.
http://david.heinemeierhansson.com/2014/tdd-is-dead-long-live-testing.htmlTDD
is dead. Long live testing.

By David Heinemeier Hansson <http://david.heinemeierhansson.com/> on April
23, 2014

Test-first fundamentalism is like abstinence-only sex ed: An unrealistic,
ineffective morality campaign for self-loathing and shaming.

It didn't start out like that. When I first discovered TDD, it was like a
courteous invitation to a better world of writing software. A mind hack to
get you going with the practice of testing where no testing had happened
before. It opened my eyes to the tranquility of a well-tested code base,
and the bliss of confidence it grants those making changes to software.

The test-first part was a wonderful set of training wheels that taught me
how to think about testing at a deeper level, but also some I quickly left
behind.

Over the years, the test-first rhetoric got louder and angrier, though.
More mean-spirited. And at times I got sucked into that fundamentalist
vortex, feeling bad about not following the true gospel. Then I'd try
test-first for a few weeks, only to drop it again when it started hurting
my designs.

It was yoyo cycle of pride, when I was able to adhere to the literal letter
of the teachings, and a crash of despair, when I wasn't. It felt like
falling off the wagon. Something to keep quiet about. Certainly not
something to admit in public. In public, I at best just alluded to not
doing test-first all the time, and at worst continued to support the
practice as "the right way". I regret that now.

Maybe it was necessary to use test-first as the counterintuitive ram for
breaking down the industry's sorry lack of automated, regression testing.
Maybe it was a parable that just wasn't intended to be a literal
description of the day-to-day workings of software writing. But whatever it
started out as, it was soon since corrupted. Used as a hammer to beat down
the nonbelievers, declare them unprofessional and unfit for writing
software. A litmus test.

Enough. No more. My name is David, and I do not write software test-first.
I refuse to apologize for that any more, much less hide it. I'm grateful
for what TDD did to open my eyes to automated regression testing, but I've
long since moved on from the design dogma.

I suggest you take a hard look at what that approach is doing to the
integrity of your system design as well. If you're willing to honestly
consider the possibility that it's not an unqualified good, it'll be like
taking the red pill. You may not like what you see after that.
So where do we go from here?

Step one is admitting there's a problem. I think we've taken that now. Step
two is to rebalance the testing spectrum from unit to system. The current
fanatical TDD experience leads to a primary focus on the unit tests,
because those are the tests capable of driving the code design (the
original justification for test-first).

I don't think that's healthy. Test-first units leads to an overly complex
web of intermediary objects and indirection in order to avoid doing
anything that's "slow". Like hitting the database. Or file IO. Or going
through the browser to test the whole system. It's given birth to some
truly horrendous monstrosities of architecture. A dense jungle of service
objects, command patterns, and worse.

I rarely unit test in the traditional sense of the word, where all
dependencies are mocked out, and thousands of tests can close in seconds.
It just hasn't been a useful way of dealing with the testing of Rails
applications. I test active record models directly, letting them hit the
database, and through the use of fixtures. Then layered on top is currently
a set of controller tests, but I'd much rather replace those with even
higher level system tests through Capybara or similar.

I think that's the direction we're heading. Less emphasis on unit tests,
because we're no longer doing test-first as a design practice, and more
emphasis on, yes, slow, system tests. (Which btw do not need to be so slow
any more, thanks to advances in parallelization and cloud runner
infrastructure).

Rails can help with this transition. Today we do nothing to encourage full
system tests. There's no default answer in the stack. That's a mistake
we're going to fix. But you don't have to wait until that's happening. Give
Capybara <https://github.com/jnicklas/capybara> a spin today, and you'll
have a good idea of where we're heading tomorrow.

But first of all take a deep breath. We're herding some sacred cows to the
slaughter right now. That's painful and bloody. TDD has been so successful
that it's interwoven in a lot of programmer identities. TDD is not just
what they do, it's who they are. We have some serious deprogramming ahead
of us as a community to get out from under that, and it's going to take
some time.

The worst thing we can do is just rush into another testing religion. I can
just imagine the golden calf of "system tests only!" right now. Please
don't go there.

Yes, test-first is dead to me. But rather than dance on its grave, I'd
rather honor its contributions than linger on the travesties. It marked an
important phase in our history, yet it's time to move on.

Long live testing.

*Continue down the rabbit hole with Why Most Unit Testing is Waste
<http://www.rbcs-us.com/documents/Why-Most-Unit-Testing-is-Waste.pdf> by
James Coplien and my RailsConf keynote on Writing Software: Part 1
<http://www.justin.tv/confreaks/b/522089408> (starts at 11:00), Part 2
<http://www.justin.tv/confreaks/b/522101045>.*

-- 
"Lute pela sua ideologia. Seja um com sua ideologia. Viva pela sua
ideologia. Morra por sua ideologia" P.R. Sarkar

EITA - Educação, Informação e Tecnologias para Autogestão
http://cirandas.net/brauliobo
http://eita.org.br

"Paramapurusha é meu pai e Parama Prakriti é minha mãe. O universo é meu
lar e todos nós somos cidadãos deste cosmo. Este universo é a imaginação da
Mente Macrocósmica, e todas as entidades estão sendo criadas, preservadas e
destruídas nas fases de extroversão e introversão do fluxo imaginativo
cósmico. No âmbito pessoal, quando uma pessoa imagina algo em sua mente,
naquele momento, essa pessoa é a única proprietária daquilo que ela
imagina, e ninguém mais. Quando um ser humano criado mentalmente caminha
por um milharal também imaginado, a pessoa imaginada não é a propriedade
desse milharal, pois ele pertence ao indivíduo que o está imaginando. Este
universo foi criado na imaginação de Brahma, a Entidade Suprema, por isso
a propriedade deste universo é de Brahma, e não dos microcosmos que também
foram criados pela imaginação de Brahma. Nenhuma propriedade deste mundo,
mutável ou imutável, pertence a um indivíduo em particular; tudo é o
patrimônio comum de todos."
Restante do texto em
http://cirandas.net/brauliobo/blog/a-problematica-de-hoje-em-dia
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