Where unit testing fails • Hacker News Board

Re: Where unit testing fails

#11

Post by peteretep » Mon, Jul 25, 2011, 10:33 AM UTC

Volpe wrote: post #8

peteretep wrote: post #4

Whut? Listen kids, testing is a tool for HELPING THE DEVELOPER, not for using to engage in a "more pious than thou" dick-swinging my Cucumber is bigger than yours idiocy. Testing is about giving YOU THE DEVELOPER useful and quick feedback about if you're on the right path, and if you've broken something, and for warning people who come after you if they've broken something. It's not an arcane methodology that somehow…

> The whole concept "test driven development" is hocus... I've worked on numerous projects where TDD has (and continues) to prove invaluable. So regardless how much experience you've got, I've had experience to the contrary, thus the "whole concept" isn't hocus. Why have you come to believe this?

It's hocus where contrasted to developer-driven testing, because Test Driven Development - as a development methodology (as opposed to a tool) - espouses that you Write All Your Tests first.

Have I had experience (and much value) out of sometimes writing tests for certain problem classes before writing any code? Yes. Changes to existing functionality are often a good candidate.

Does TDD as a methodology suggest you should ALWAYS write your tests first? Everything I've read suggests so.

And "as any fule kno" [sic], this is idioicy during a design or hacking or greenfield phase of development. Allowing your tests to dictate your code (rather than influence the design of modular code) and to dictate your design because you wrote over-invasive test.

tl;dr: Writing tests before code works pretty well in some situations. Test Driven Development, as handed down to us mortals by Agile Testing Experts and other assorted shills, is hocus.

Re: Where unit testing fails

#12

Post by elmomalmo » Mon, Jul 25, 2011, 10:47 AM UTC

peteretep wrote: post #11

Volpe wrote: post #8

Earlier quoted context omitted.

> The whole concept "test driven development" is hocus... I've worked on numerous projects where TDD has (and continues) to prove invaluable. So regardless how much experience you've got, I've had experience to the contrary, thus the "whole concept" isn't hocus. Why have you come to believe this?

It's hocus where contrasted to developer-driven testing, because Test Driven Development - as a development methodology (as opposed to a tool) - espouses that you Write All Your Tests first. Have I had experience (and much value) out of sometimes writing tests for certain problem classes before writing any code? Yes. Changes to existing functionality are often a good candidate. Does TDD as a methodology suggest you s…

This is a common misconception. TDD does not 'espouse' in any way that you write all your tests first. Nothing I have read suggests so.

For me, TDD, in practice means switching back and forth between writing tests and production code. That is, write some test code, run, fail, fix the production code, write some more test code. It is incremental.

EDIT: Fixed a typo

Re: Where unit testing fails

#13

Post by fafssaf » Mon, Jul 25, 2011, 10:58 AM UTC

What are some cases that you would and wouldn't use unit tests? Igal is doing a webinar https://www2.gotomeeting.com/register/545851563

Re: Where unit testing fails

#14

Post by Volpe » Mon, Jul 25, 2011, 11:03 AM UTC

peteretep wrote: post #11

Volpe wrote: post #8

Earlier quoted context omitted.

> The whole concept "test driven development" is hocus... I've worked on numerous projects where TDD has (and continues) to prove invaluable. So regardless how much experience you've got, I've had experience to the contrary, thus the "whole concept" isn't hocus. Why have you come to believe this?

It's hocus where contrasted to developer-driven testing, because Test Driven Development - as a development methodology (as opposed to a tool) - espouses that you Write All Your Tests first. Have I had experience (and much value) out of sometimes writing tests for certain problem classes before writing any code? Yes. Changes to existing functionality are often a good candidate. Does TDD as a methodology suggest you s…

> Writing tests before code works pretty well in some situations. Test Driven Development, as handed down to us mortals by Agile Testing Experts and other assorted shills, is hocus.

What? So it works in some situations, but not all. Thus hocus?

I'm no 'Agile Testing Expert', but I have worked for the last 2-3 years doing TDD exclusively (as in ALWAYS writing tests first). It isn't hocus. It is effective. I can understand it doesn't suit all problems, and can potentially be a hinderance sometimes, but that is the same for ANY methodology/practice. I don't quite understand your hostility towards it.

What do you mean by 'developer driven testing'?

Re: Where unit testing fails

#15

Post by arethuza » Mon, Jul 25, 2011, 11:26 AM UTC

peteretep wrote: post #11

Volpe wrote: post #8

Earlier quoted context omitted.

> The whole concept "test driven development" is hocus... I've worked on numerous projects where TDD has (and continues) to prove invaluable. So regardless how much experience you've got, I've had experience to the contrary, thus the "whole concept" isn't hocus. Why have you come to believe this?

It's hocus where contrasted to developer-driven testing, because Test Driven Development - as a development methodology (as opposed to a tool) - espouses that you Write All Your Tests first. Have I had experience (and much value) out of sometimes writing tests for certain problem classes before writing any code? Yes. Changes to existing functionality are often a good candidate. Does TDD as a methodology suggest you s…

I don't think I've ever seen a description of TDD that suggests you write all of your tests before writing any production code - rather you iteratively write some tests, have them fail then write the code to make them work and then see the tests pass, repeating that process until you have implemented everything you need.

Re: Where unit testing fails

#16

Post by tomjen3 » Mon, Jul 25, 2011, 11:56 AM UTC

Volpe wrote: post #14

peteretep wrote: post #11

Earlier quoted context omitted.

It's hocus where contrasted to developer-driven testing, because Test Driven Development - as a development methodology (as opposed to a tool) - espouses that you Write All Your Tests first. Have I had experience (and much value) out of sometimes writing tests for certain problem classes before writing any code? Yes. Changes to existing functionality are often a good candidate. Does TDD as a methodology suggest you s…

> Writing tests before code works pretty well in some situations. Test Driven Development, as handed down to us mortals by Agile Testing Experts and other assorted shills, is hocus. What? So it works in some situations, but not all. Thus hocus? I'm no 'Agile Testing Expert', but I have worked for the last 2-3 years doing TDD exclusively (as in ALWAYS writing tests first). It isn't hocus. It is effective. I can unders…

The hocus is not that you can use TDD, if, in your professional judgment, you believe that to be the best solution to the problem.

The hocus is that you must use it, because some guru said so.

Re: Where unit testing fails

#17

Post by rimantas » Mon, Jul 25, 2011, 12:01 PM UTC

chrislloyd wrote: post #7

I can't help but appreciate the irony of a link titled "Where unit testing fails" leading to a WordPress database connection error.

So you think unit tests would help with that?

Re: Where unit testing fails

#18

Post by smackay » Mon, Jul 25, 2011, 12:29 PM UTC

Volpe wrote: post #8

peteretep wrote: post #4

Whut? Listen kids, testing is a tool for HELPING THE DEVELOPER, not for using to engage in a "more pious than thou" dick-swinging my Cucumber is bigger than yours idiocy. Testing is about giving YOU THE DEVELOPER useful and quick feedback about if you're on the right path, and if you've broken something, and for warning people who come after you if they've broken something. It's not an arcane methodology that somehow…

> The whole concept "test driven development" is hocus... I've worked on numerous projects where TDD has (and continues) to prove invaluable. So regardless how much experience you've got, I've had experience to the contrary, thus the "whole concept" isn't hocus. Why have you come to believe this?

The issue/argument here is not that writing tests is worthless but that in many cases the approach of "if we write enough tests then the code that solves the problem will eventually emerge" is doomed to failure or at least results in an extremely verbose approach to development.

Re: Where unit testing fails

#19

Post by jsdalton » Mon, Jul 25, 2011, 12:32 PM UTC

latch wrote: post #6

There are a couple tricks to effective unit testing. Ultimately though, the goal is to write non-brittle tests. That is, tests that won't break due to unrelated changes. Get this wrong and the cost of maintaining your tests will outweigh the benefits. Achieving this, in my experience, comes down to disciplined used of mocks and stubs. I've seen people lean too heavily on them, or not heavily enough. The biggest probl…

Can you expand a bit on the distinction you're making between mocks and stubs, and why you believe stubs are both underused and useful?

Perhaps I'm doing it wrong, but I've found in my experience that bugs I miss in testing increase proportionally with my use of mocks or stubs. Invariably, when I'm forced to stub something and replicate its behavior I miss something subtle that comes back to bite me.

Re: Where unit testing fails

#20

Post by berntb » Mon, Jul 25, 2011, 12:36 PM UTC

Volpe wrote: post #14

peteretep wrote: post #11

Earlier quoted context omitted.

It's hocus where contrasted to developer-driven testing, because Test Driven Development - as a development methodology (as opposed to a tool) - espouses that you Write All Your Tests first. Have I had experience (and much value) out of sometimes writing tests for certain problem classes before writing any code? Yes. Changes to existing functionality are often a good candidate. Does TDD as a methodology suggest you s…

> Writing tests before code works pretty well in some situations. Test Driven Development, as handed down to us mortals by Agile Testing Experts and other assorted shills, is hocus. What? So it works in some situations, but not all. Thus hocus? I'm no 'Agile Testing Expert', but I have worked for the last 2-3 years doing TDD exclusively (as in ALWAYS writing tests first). It isn't hocus. It is effective. I can unders…

Excuse me for interrupting the budding flame war, but I have a question regarding the subject, which you seem qualified to answer? :-)

My experience is the same as (what I believe is) the usual criticism of tests-first.

I often need to rethink the API to my functions/methods, sometimes more than once. This goes for both external and internal APIs, so it doesn't help with detailed interface specifications between modules.

Test-first is a problem, since it needs a fixed interface before I'm ready to lock down the interface.

I tend to instead write inside-out; a few pages of code and then write tests for that code. That model isn't really kosher/halal/etc, according to TDD?