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Testing is better than data structures and algorithms

nedbatchelder.com

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Re: Testing is better than data structures and algorithms

#11

Post by ChrisMarshallNY »

I agree with the article, but I'll bet a lot of others, don't. Discussions on Code Quality, don't fare well, here. Wouldn't surprise me, if the article already has flags.

Of course, "testing," is in the eye of the beholder.

Some folks are completely into TDD, and insist that you need to have 100% code coverage tests, before writing one line of application code, and some folks think that 100% code coverage unit tests, means that the system is fully tested.

I've learned that it's a bit more nuanced than this[0].

[0] https://littlegreenviper.com/testing-harness-vs-unit/

Re: Testing is better than data structures and algorithms

#12

Post by Jtsummers »

wjrb wrote: post #2

Are there any resources out there that anyone can recommend for learning testing in the way the author describes? In-the-trenches experience (especially "good" or "doing it right" experience) can be hard to come by; and why not stand on the shoulders of giants when learning it the first time?

Working Effectively with Legacy Code by Michael Feathers. It spends a lot of time on how to introduce testability into existing software systems that were not designed for testing.

Property-Based Testing with PropEr, Erlang, and Elixir by Fred Hebert. While a book about a particular tool (PropEr) and pair of languages (Erlang and Elixir), it's a solid introduction to property-based testing. The techniques described transfer well to other PBT systems and other languages.

Test-Driven Development by Kent Beck.

https://www.fuzzingbook.org/ by Zeller et al. and https://www.debuggingbook.org/ by Andreas Zeller. The latter is technically about debugging, but it has some specific techniques that you can incorporate into how you test software. Like Delta Debugging, also described in a paper by Zeller et al. https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=988....

I'm not sure of other books I can recommend, the rest I know is from learning on the job or studying specific tooling and techniques.

Re: Testing is better than data structures and algorithms

#13

Post by pshirshov »

cogman10 wrote: post #10
pshirshov wrote: post #4

Pure bullshit and incompetence. > esoteric things like Bloom filters, so you can find them later in the unlikely case you need them. They are not esoteric, they are trivial and extremely useful in many cases. > Less DSA, more testing. Testing can't cover all the cases by definition, why not property testing? Why not formal proofs? Plus, in our days, it's easy to delegate testcase writing to LLMs, while they literally…

> extremely useful in many cases. I've not ran into a case where I can apply a bloom filter. I keep looking because it always seems like it'd be useful. The problem I have is bloom filter has practically reverse characteristics from what I want. It gives false positives and true negatives. I most often want true positives and false negatives.

Assume that you need to build a large-scale search or analytics tool for example. All the sketch data structures (like cuckoo filters and especially hypermihashes) are extremely useful in these scenarios.

Re: Testing is better than data structures and algorithms

#14

Post by hvb2 »

cogman10 wrote: post #9
hvb2 wrote: post #6

This feels backwards. When you have a good understanding of data structures you have the luxury of testing. If you focus on testing over data structures, you might end up testing something that you didn't need to test because you used the wrong data structures. IMHO too often people dont consider big O because it works fine with their 10 row test case.... And then it grinds to a halt when given a real problem

That wasn't the thrust of the article. The article is saying that it's more important to write tests than it is to learn how to write data structures. It specifically says you should learn which data structures you should use, but don't focus on knowing how to implement all them. It calls out, specifically, that you should know that `sort` exists but you really don't need to know how to implement quicksort vs selecti…

No, it says learn data structures first, then focus on testing.

You don't have to go super deep on all the sort algorithms, sure. That's like saying that learning testing implies writing a mocking library

Re: Testing is better than data structures and algorithms

#15

Post by Jtsummers »

marcosdumay wrote: post #3

When testing job candidates, sure, no doubt about that. For for learning, no, it's not. You should not spend as much time learning testing as you spend leaning data structures.

I feel like this mischaracterizes the blog. You seem to be taking this:

> People should spend less time learning DSA, more time learning testing.

And reading it as "More total time should be spent on learning testing than the total time spent learning DSA". That's one reading, another is that people are studying DSA too much, and testing too little. The ratio of total time can still be in favor of studying DSA more, but maybe instead of 10:1 it should be more like 8:1 or 5:1.

Re: Testing is better than data structures and algorithms

#16

Post by glitchc »

The article fails to demonstrate how code-tests result in objectively better code. Many comp sci programs have courses on testing that cover TDD, unit testing and fuzzing, among other topics.

Yet much of the safety critical code we rely on for critical infrastructure (nuclear reactors, aircraft, drones, etc) is not tested in-situ. It is tested via simulation, but there's minimal testing in the operating environment which can be quite complex. Instead the code follows carefully chosen design patterns, data structures and algorithms, to ensure that the code is hazard-free, fault-tolerant and capable of graceful degradation.

So, testing has its place, but testing is really no better than simulation. And in simulation, the outputs are only as good as the inputs. It cannot guarantee code safety and is not a substitute for good software design (read: structures and algorithms).

Having said that, fuzzing is a great way to find bugs in your code, and highly recommended for any software that exposes an API to other systems.

Re: Testing is better than data structures and algorithms

#18

Post by danielmarkbruce »

This will annoy a lot of folks, but:

1 - If you work on large scale software systems, especially infrastructure software of most types then you need to know and understand DSA and feel it in your bones.

2 - Most people work on crud apps or similar and don't really need to know this stuff. Many people in this camp don't realize that people working on 1 really do need to know this stuff.

What someone says on this topic says more about what things they have worked on in their life than anything else.

Re: Testing is better than data structures and algorithms

#19

Post by MoreQARespect »

glitchc wrote: post #16

The article fails to demonstrate how code-tests result in objectively better code. Many comp sci programs have courses on testing that cover TDD, unit testing and fuzzing, among other topics. Yet much of the safety critical code we rely on for critical infrastructure (nuclear reactors, aircraft, drones, etc) is not tested in-situ. It is tested via simulation, but there's minimal testing in the operating environment w…

>fails to demonstrate how code-tests result in objectively better code.

Tests give the freedom to refactor which results in better code.

>So, testing has its place, but testing is really no better than simulation

Testing IS simulation and simulation IS testing.

>And in simulation, the outputs are only as good as the inputs. It cannot guarantee code safety

Only juniors think that you can get guarantees of code safety. Seniors look for ways to de-risk code, knowing that you're always trending towards a minima.

One of the key skills in testing is defining good, realistic inputs.

Re: Testing is better than data structures and algorithms

#20

Post by karmakaze »

The context what you should spend time to learn starting out. TL;DR

> Here is what I think in-the-trenches software engineers should know about data structures and algorithms: [...]

> If you want to prepare yourself for a career, and also stand out in job interviews, learn how to write tests: [...]

I feel like I keep writing these little context comments to fix the problem of clickbait titles or those lacking context. It helps to frame the rest of the comments which might be coming at it from different angles.

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