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Sensible Software Engineering

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Re: Sensible Software Engineering

#21

Post by userbinator »

jasode wrote: post #2

>Bugs are correlated with lines of code and TDD forces writing more code so how can it reduce bug counts? If the test code has no bugs then just write the rest of the code in the same style I'm not advocating for TDD (the programmer methodology in the IDE) but the author's explanation about "test code" isn't correct. Code written for explicit purposes of a test to exercise other code has been shown to increase correc…

The question that always comes to mind whenever testing is discussed is "how do you know the test code is itself free of bugs?"

I distinctively remember once posing that question in a meeting about testing, and a manager replying --- seriously --- with "then perhaps the test code should itself have tests." Someone else must've come up with that before too, because (at a different job) I've also worked on a codebase where a surprising number of tests were basically testing the function of another test.

Re: Sensible Software Engineering

#22

Post by WrtCdEvrydy »

pytester wrote: post #11
leetrout wrote: post #9

Earlier quoted context omitted.

I am a big fan of Nomad's scheduler and the code is easy to pull in to an existing Go project. It doesn't have everything Kubernetes has but I don't think it needs it, either. Kubernetes has for sure won the popularity contest but the overhead involved in running it The Right Way™ on your own is a lot. Given what I've seen I would advocate for OpenShift if you like RedHat products / projects or sticking with Kubernet…

I have a sneaking suspicion that Kubernetes is another Ruby on Rails waiting to happen: https://trends.google.com/trends/explore?date=all&geo=US&q=r...

Good for me, I must made about 500,000 from moving Rails to other more modern stacks... I'll learn Kubernetes just as it dies off and start moving people's shit to whatever's next.

Re: Sensible Software Engineering

#23

Post by wildmanx »

> Bugs are correlated with lines of code and TDD forces writing more code so how can it reduce bug counts? If the test code has no bugs then just write the rest of the code in the same style

Nobody has pointed out the fault in this reasoning yet, so I will.

The linear relationship lines-of-code vs. total-bug-count is based on independence of bug introduction in different parts of the code. That is, introducing a bug in line 10000 is more-or-less independent of adding line 20000. For product code that is arguably the case, but adding test code into the mix, this basic assumption doesn't just not hold, but it's turned upside down.

Test code is not customer-visible, but only dev-visible, with the sole purpose of finding bugs. Thus, adding test code to a code base decreases the average probability of a bug for lines of product code. More formally, if you have N lines of product code and thus c * N bugs for some fraction c, then adding M lines of test code does not increase the number of customer-visible bugs to c * (N + M). Instead, it reduces that number to c' * N with c'I agree with the rest of the post though.

Re: Sensible Software Engineering

#24

Post by james_s_tayler »

WrtCdEvrydy wrote: post #22
pytester wrote: post #11

Earlier quoted context omitted.

I have a sneaking suspicion that Kubernetes is another Ruby on Rails waiting to happen: https://trends.google.com/trends/explore?date=all&geo=US&q=r...

Good for me, I must made about 500,000 from moving Rails to other more modern stacks... I'll learn Kubernetes just as it dies off and start moving people's shit to whatever's next.

That has to be one of the best strategies out there. So long as you just read the trends right.

Re: Sensible Software Engineering

#25

Post by sombremesa »

wildmanx wrote: post #23

> Bugs are correlated with lines of code and TDD forces writing more code so how can it reduce bug counts? If the test code has no bugs then just write the rest of the code in the same style Nobody has pointed out the fault in this reasoning yet, so I will. The linear relationship lines-of-code vs. total-bug-count is based on independence of bug introduction in different parts of the code. That is, introducing a bug…

Tests don't exist for solving bugs as much as they exist to prevent regression. Writing exhaustive tests is not sufficient to bring c' to zero, because some of those bugs exist because of the developer's own presumptions about how code should behave.

Re: Sensible Software Engineering

#26

Post by danmaz74 »

jasode wrote: post #2

>Bugs are correlated with lines of code and TDD forces writing more code so how can it reduce bug counts? If the test code has no bugs then just write the rest of the code in the same style I'm not advocating for TDD (the programmer methodology in the IDE) but the author's explanation about "test code" isn't correct. Code written for explicit purposes of a test to exercise other code has been shown to increase correc…

What the author didn't consider is that test code adds redundancy to the code base - if you introduce a bug only in the test code, while the tested code is correct, will make the test fail, and you will fix this.

Where instead the amount of test code can become a problem, in my experience, is with maintenance. Efficiency is very important.

Re: Sensible Software Engineering

#27

Post by gilbetron »

wildmanx wrote: post #23

> Bugs are correlated with lines of code and TDD forces writing more code so how can it reduce bug counts? If the test code has no bugs then just write the rest of the code in the same style Nobody has pointed out the fault in this reasoning yet, so I will. The linear relationship lines-of-code vs. total-bug-count is based on independence of bug introduction in different parts of the code. That is, introducing a bug…

Do you have an actual source that corroborates that with actual data? It seems true, but I haven't found anything that actually tests the premise. I've found studies that show that code with lots of unit tests tends to be more bug free, but not anything about whether unit tests increases (or decreases) development time or whether test code actually has less bugs. I think it would be interesting if there is also a measure of code complexity, and if less complex test code correlates with less bugs in the test code.

Re: Sensible Software Engineering

#28

Post by gjm11 »

userbinator wrote: post #21
jasode wrote: post #2

>Bugs are correlated with lines of code and TDD forces writing more code so how can it reduce bug counts? If the test code has no bugs then just write the rest of the code in the same style I'm not advocating for TDD (the programmer methodology in the IDE) but the author's explanation about "test code" isn't correct. Code written for explicit purposes of a test to exercise other code has been shown to increase correc…

The question that always comes to mind whenever testing is discussed is "how do you know the test code is itself free of bugs?" I distinctively remember once posing that question in a meeting about testing, and a manager replying --- seriously --- with "then perhaps the test code should itself have tests." Someone else must've come up with that before too, because (at a different job) I've also worked on a codebase w…

You don't know that the test code is free of bugs. You don't need to.

Case 0: No bugs in the test code. All is well.

Case 1: Bug in the test code that causes some bugs in the real code not to get caught. That's bad, but you're no worse off than if you didn't have the test at all.

Case 2: Bug in the test code that causes correct real code to look buggy. Result: the test fails, you look for problems, most likely you find that the problem is in the test code and fix it. Going forward, you have a working test.

Case 3: Bug in the test code that makes something else break. This can happen and is genuinely bad, but (1) it only affects testing, not your actual product, and (2) most bugs don't behave that way.

The test code is a net win if the bugs it catches in your real code are worth the effort of writing and debugging the test code. That's no less true on account of the possibility of bugs in the test code. It just means that when you estimate the benefit you have to be aware that sometimes the tests might be less effective because of bugs, and when you estimate the cost you have to be aware that you have to debug the code, not just write it the first time. And then you just ... decide what's the best tradeoff, just like everything else in engineering.

(And no, you don't need tests for your test code. The test code is a test for itself as well as for the code it's testing.)

Re: Sensible Software Engineering

#29

Post by danmaz74 »

WrtCdEvrydy wrote: post #22
pytester wrote: post #11

Earlier quoted context omitted.

I have a sneaking suspicion that Kubernetes is another Ruby on Rails waiting to happen: https://trends.google.com/trends/explore?date=all&geo=US&q=r...

Good for me, I must made about 500,000 from moving Rails to other more modern stacks... I'll learn Kubernetes just as it dies off and start moving people's shit to whatever's next.

Out of curiosity, which more modern stacks were those?

Re: Sensible Software Engineering

#30

Post by Aeolun »

gilbetron wrote: post #27
wildmanx wrote: post #23

> Bugs are correlated with lines of code and TDD forces writing more code so how can it reduce bug counts? If the test code has no bugs then just write the rest of the code in the same style Nobody has pointed out the fault in this reasoning yet, so I will. The linear relationship lines-of-code vs. total-bug-count is based on independence of bug introduction in different parts of the code. That is, introducing a bug…

Do you have an actual source that corroborates that with actual data? It seems true, but I haven't found anything that actually tests the premise. I've found studies that show that code with lots of unit tests tends to be more bug free, but not anything about whether unit tests increases (or decreases) development time or whether test code actually has less bugs. I think it would be interesting if there is also a mea…

Arguing from the point of logic and formalisms the author is talking about, this would seem to be true.
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