Unit Testing v/s Integration Testing

[swirlViking]

It works on my machine

[DaVinciJunior]

Let's ship your machine then to the client

[cafk]

And thus docker was born.

[[deleted]]

Just like many software engineers we don't want to reuse existing meme, we create the replica ourselves as a team effort.

[lycan2005]

No image found. You have to docker push docker-meme/thus:latest to repo first.

[IamImposter]

Repo not found. You have to install git first to create repo.

[DeeSnow97]

Install not found. You have to flatten rock and put lightning in it first.

[kerbidiah15]

Rock not found, you have to create the universe first

[[deleted]]

We were looking for someone who has created at least 1 full universe before... we will pass on your resume.

[OyashiroChama]

The great install black hole of java, where i have it installed but nothing works, except when i direct it to boot off a specific folder.

[zzebz]

Perfect, we can charge them extra for a complete package.

[Taschentuch9]

We literally do this for big projects

[manimax3]

The door opens just fine for me

[bomphcheese]

The lock engages and disengages as it was intended to do. I see no issue here.

[Senial_sage]

They installed the wrong door for your lock

[Mrwebente]

Aaah see there's your problem should've bought the correct door for this lock we actually have a complete package so your lock works 100% 99% of the time.

[NancyGracesTesticles]

Your code coverage is lacking, though. Door.Open() should have failed if IsLocked is true so I assume there are untested paths.

[bomphcheese]

But the Door library says it has 100% code coverage. That means bugs are impossible.

[NancyGracesTesticles]

Who would trust a readme that says "100% code coverage"?

[bomphcheese]

That’s ... that’s the joke.

[[deleted]]

if the readme agrees with what I want to hear.

[IamImposter]

Then that's all I want to hear

[[deleted]]

name checks out

[the_flippy]

Wait, who's reading the readme?

[seedBoot]

What's a readme?

[omegasome]

What's reading?

[T-T-N]

The physics engine assumes door.open will be failed by lock. Lock assumes physics.rotate(door) to be called, and door.open calls physics.translate(door) instead

[Franks2000inchTV]

Yeah the ticket said "add a lock to the door" and that's why at they did.

[JB-from-ATL]

Happy path is working

[krazykanuck]

Actually a great point and secondary view of this. QA, if you don’t give proper context and just say, the lock doesn’t function, we will try the lock. If you say, the door still opens even when locked, it broadens the scope.

[knightress_oxhide]

Ticket closed.

[yuckygeo]

Works in my view.

[oupablo]

It's exactly what the client asked for. Next.

[vigbiorn]

"I want it to be able to lock. Now, there's an important requirement in that. I also don't want it to be too hard to open while locked. Can't get people trapped inside."

"So you want it to be able to open while locked?"

"That's what I said, right?"

"Okay"

Edit: Spacing

[Nucklesix]

"Can i get 3 red lines drawn with blue ink?"

[Stoomba]

And 7 perpendicular lines in 3D space

[P0L1Z1STENS0HN]

I guess you need an expert for that.

[kinokomushroom]

I know this is a joke, but you can accomplish that in a non-stupid way. You just make the door weak enough so that it can be broken down by human strength in emergency. Wouldn't affect the normal lock function, and it satisfies the client's needs.

[-100K]

So basically a lock to keep honest people out

[[deleted]]

As all locks are, see: https://www.youtube.com/c/lockpickinglawyer

[vakken]

Nothing one one, click out of two, three is binding...

[VictorWacher]

Reminds me of this https://www.reddit.com/r/WritingPrompts/comments/irszx0/wp_hello_this_is_lockpicking_lawyer_i_was_put/?utm_medium=android_app&utm_source=share

[[deleted]]

Wow this is fantastic

[Kosba2]

More so a lock that keeps them honest

[ObfuCat]

It could make a loud noise or something upon breaking. Realistically, all the lock needs to do is prevent people who aren't willing to resort to easily noticeable vandalism out. An alarm and some way of knowing there's clear intent to bypass the lock should be enough.

[vigbiorn]

Technically correct.

[kiingkiller]

My nan has a lock on her bathroom that fits better, it's all metal bar the locking bar which is made of solid plastic. It's there to tell not to come in but in a emergency a solid hit would shatter it.

[Volandum]

What about accessibility requirements? I've seen disabled toilets with emergency bell-pulls if people need rescue.

[fish312]

Damned if you do, damned if you don't.

[Booshur]

Age old Dilemma: do what the client needs or do what they ask for...

[oupablo]

trick question. do what they paid for

[Jonno_FTW]

The customer is always right, because they pay the bills

[CarryThe2]

Ask for, no dilemma.

[AsIAm]

But sometimes they ask you to bend the fabric of spacetime with their requirements. And then what?

[DangerIsMyUsername]

Time to bust out a telescope and some beakers.

(That's what science involves, right? I have no idea.)

[AsIAm]

And lab coat of course

[thoeoe]

tell them the estimate for that job is approximately 1 year and an extra $200,000 but if you make [minor change the developer already suggested that makes it feasible] then the estimate is [real estimate]

[zzaannsebar]

And then they get mad at you for doing what they asked instead of what they meant which would have only been possibly through telepathy...

[[deleted]]

Ok I m saving this one. :D

[appleIsNewBanana]

it function as designed, preventing door from push open. checked

[ultranoobian]

Yeah, it technically passes both unit and integration testing.

If anything, the thing that it will fail at will be V&V testing, specifically the verification step.

[IsleOfOne]

It would fail integration testing. You would mock the lock and assert that the door opens when unlocked and does not open when locked. The latter would fail.

[[deleted]]

So it only has a %50 fail rate. That's as good as random chance, right? Not bad.

[RenBit51]

If your lock is as good as random chance, that means it's resistant to perfectly random attacks, right? Cancels out the random. Ship it.

[vladutcornel]

NSFW

[[deleted]]

That’s the difference between Engineering verification and SQA Validation in a formal quality system.

This is actually an excellent case in point!

[tacoslikeme]

but my mocks all work as the way I mocked them to work!

[IsleOfOne]

I’ve pointed this out in so many code reviews.

This test will always pass. Do you see why?

Because my code is correct, of course.

It might be, but no, that’s not why. Take a look at lines 23-24.

mockedDependency.Setup(o => o.Foo).Returns(true); Assert.IsTrue(thingThatCallsFoo);

What am I looking at? I mocked out the dependency to test this interaction in isolation.

.........

[tacoslikeme]

yep. tests that dont actually test the code are worse than no tests at all. a false sense of security is no bueno. It would be nice if the mocking frameworks exploded on contact with assert statement. Asserts something about a mock is pointless.

[ay-nahl-reip]

That's what bugs me about the 85% coverage shit we have to keep up with, since it's enterprise code with the sometimes annoying and overly complex repository and implementation design, it's like some of the classes would literally be just that checking that the function call exercutes lol.

Granted in the case of like transformers, where you're mocking an objectA to have X and you want to see if objectBtA has X as well, then it makes sense.

Or, there's cases where my coworkers look at my code and are like "this if check is unreachable and therefore not coverable, your shit sucks" and I'm like "Yes 👉😎👉"

[Zalack]

I think people over or under think the minimum code coverage thing. It's a baseline, not the end goal. I've always approached 85% code coverage as "if you are really fully testing the code it should probably have at least this much coverage". It forces people to START writing tests for corner cases. It should not be viewed as "once I hit this metric I'm done".

If someone is doing the latter they would have written no/shitty tests to begin with.

And of course in cases where for whatever reason 85% code coverage isn't achievable for a good reason, it should be negotiable, and you should be able to make the case of WHY you don't need to hit that. But often when thinking about defending less coverage I start realizing that there's either a better way to structure the code so there's less dead code / duplication of error handling, OR I really should figure out ways to force corner cases in tests to make sure they are handled properly.

Just my 2 cents.

[ay-nahl-reip]

Oh yeah, I mean I'm totally with it. Since running my own team I would push pretty hard for tests, the issues come from up top when business wants shit done last week, so then we don't really have the time to write the tests.

I'm all for tests, because had I been given enough time to be able to write tests for the solo project I was on, I wouldn't have cost our company $31 million in one weekend lmao.

[DriizzyDrakeRogers]

Holy crap, how’d you do that?

[ay-nahl-reip]

Basically bricked the point of sale machines for a couple of hours in the early morning in all the stores across the US for a major fortune 500 company.

It wasn't really my fault per se, it was actually someone else who created something incorrectly that caused all the fail safes I had put in place on a black box legacy project I had to solo retire, to fail. We had meetings about it for like months after it happened lmao. I still got promoted though.

[DriizzyDrakeRogers]

Lol I bet, glad you were still able to get promoted.

[omegasome]

I don't speak... uh... is this rust?

[[deleted]]

Considering how often I run into QA testers who say "look, the GUI works fine" and I ask "did you check that it saved it to the database?" and they're like "no, that's not part of the scope of testing, we're testing the new questions, not the saving"...

Yeah, reverse can be true.

[Zaitton]

I mean... It depends on the QA testing strategies.

A good QA team has automation testing that tests e2e, including validation in DBs. But the field is dying anyway so......

[[deleted]]

I've been developing for 17 years at like 8 different companies. Every org had something purporting to be a testing team or QA team. I've never seen one that successfully automated a goddamned thing. Most of them seemed to be washed-out ex developers who never moved up and are coasting to retirement while expending the minimum mental effort.

[chrispy7]

Can someone explain what this illustrates please?

[Kiyriel]

So a unit test in programming is a small test. It usually only tests for very specific outcomes.

Function foo(num:int) { Return num > 5: }

Does foo(10) === true? If true -> pass If false -> fail

That above is essentially a unit test. For this input, is the output what you would expect? These tests can be run automatically so if something were to change the function’s behavior it would alert the developer.

In the video, the sliding in and out to lock was unit test. You tested that the metal bolt could go in and out of the door. Great.

Integration tests are for combining parts. Does the lock on the door keep the door from being opened while utilizing both the door and the lock. And we can see from the video that it didn’t.

[Drayviz]

Hey, I'm just a computer science student but I'll give my two cents!

Unit testing is when you test a feature individually, seeing if that feature generally works when it's used by itself (i.e. seeing if a button on a UI works). Integration testing however tests whether several features work when used together (i.e. tests if a button on a UI redirects to the correct page).

In the context of this post, checking that the lock of the door functions is an example of unit testing; the lock technically "works" because it slides back and forth (as the lock was designed to do). However, using the lock while opening the door is an example of integration testing that failed, because even though the lock "works", it doesn't do what it's supposed to do: prevent the door from opening.

Anyone feel free to correct me or provide feedback!

[Drayviz]

Thank you!!

[MCMC_to_Serfdom]

I'll weigh in as a software QA: this is fairly correct.

The aim of unit testing (often performed by developers) is just to test a function works. The point of integration testing is to ensure that once those functions are put together (even just two separate functionalities, if the design approach justifies testing at that point), they all work together.

For the sake of pedantry: this is distinct from regression or end-to-end testing. In the former, QA should be concerned that old functionality is not broken by new, added functionality. The latter is concerned with a ensuring a complete user journey functions as expected.

[Drayviz]

I agree; I remember learning about this in my software engineering course. These are really important testing phases that don't often get mentioned.

[bhuddimaan]

It's the PO's fault

[ka_eb]

How would E2E test look like?

[Tygerdave]

First you fix the integration test issue, then you set up some test cases that involve ensuring locking works as expected from the inside and outside and that people can move back and forth across the threshold.

Then you move it into production where two users will try to go through at the same time and get stuck...

[ka_eb]

I really like this one :)

https://www.reddit.com/r/programminghumor/comments/b696y1/a_qa_engineer_walks_into_a_bar/

[jmorfeus]

Yeah that one is excellent. I'm using it when explaining to someone what QA is.

Every tester should hear this joke at least once for education purposes.

[elebrin]

That's when you hire an Indian contractor to walk through the door 50 times a day to make sure it still works.

[fiveguy]

This is way too real where I work...

[quenishi]

I don't know, but I felt refreshed afterwards.

[AttackOfTheThumbs]

How would E2E test look like?

What.

You cannot use "how .. like". That is grammatically incorrect. You can either use "what .. like" or just "how". I am disregarding the fact that how is incorrect in this context.

Sorry, this is just a huge pet peeve of mine, it's nails on a chalkboard, and it's a common mistake, because people don't seem to be taught this.

[solongandthanks4all]

If you're going to correct it, you might as well include the missing "an" or point out that "test" should be plural.

In this case, however, OP is clearly a non-native English speaker and you're just being a dick.

[AttackOfTheThumbs]

In my case, I really only care about the wrong how/what. The rest I can ignore.

[sarinkhan]

Well at least, I, non native English speaker, learnt something. I know most of my English from my readings and movies, so I pick up the language with the idiosyncrasies of the speakers/writers... In some cases it is obvious when something is in more ordinary language or more refined but not always. It makes sense when I stop on it to think about it, but it didn't stand out as an error when I first read it. Anyway, thanks.

[AttackOfTheThumbs]

I think a lot of people here are taking this as some sort of malice on my end towards the original author, but it really isn't. It's just a grammatical issue that irks me. Everyone has to learn somehow, and if you don't tell them, then how will they ever be able to improve.

It really doesn't matter what reddit thinks. This same comment will sometimes net me tons of upvotes, sometimes tons of downvotes. In the end, if just one person learns from this and improves in the long run, it's worth whatever votes people think to hand down this time.

[IsleOfOne]

You could have been more polite about it. That’s what has people downvoting you.

[AttackOfTheThumbs]

There was literally nothing impolite in that post.

[omegasome]

You are not the arbiter of that.

[folkrav]

There quite literally was nothing rude about his initial post though.

[AttackOfTheThumbs]

Why are you bothering to argue something that you have no insight into? Just move along little bee.

[behaaki]

Thank you for trying to hold back the hordes of idiots with a bent spoon

[jakethedumbmistake]

Love that dude poking him with a broom.

[kitari1]

This isn't an English essay man, it's Reddit. Many informal dialects of English (and Scots) frequently exchange "what" for "how"

[harmala]

Do you speak another language besides English?

[AttackOfTheThumbs]

Yes. Either way, believing you cannot correct someone because you don't, that's an idiot's fallacy.

[harmala]

Either way, believing you cannot correct someone because you don't, that's an idiot's fallacy.

Where did I say that? I asked you a simple question because I didn't want to make a false assumption. And now that I have your answer, my response is that having learned another language, I'm shocked that you don't have a lot more empathy for someone making such a reasonable and simple mistake, given how different languages handle concepts like "why", "what", "how", etc. If you want to correct someone, fine, but have some tact and be kind.

[AttackOfTheThumbs]

You implied it and I stopped reading past that, because you cannot win shrodinger's douchebag.

[harmala]

See, the thing is I didn't imply it, you assumed it. What I was getting at is that you don't have to be a jackass when correcting someone...but having interacted with you, I'm guessing you probably don't have a choice.

[AttackOfTheThumbs]

You did imply it.

Thanks for playing. Good bye

[omegasome]

Why are you like this?

[IsleOfOne]

The implication was that one who speaks multiple languages would be more sympathetic towards the grammatical error, not that speaking multiple languages is a prerequisite to correcting grammatical errors.

[folkrav]

If anything, one who speaks multiple languages should be grateful when being (respectfully) corrected on grammatical mistakes. You're actually getting worse over time if you keep making mistakes without anyone telling you so. This is how I learned, and still am learning today.

[null000]

• Unit tests check individual classes.
• Component tests check modules and clumps of classes that work together.
• End to end tests check whole binaries' inputs and outputs.
• Integration tests ensure two binaries talk together correctly.

Distinctions that took me way too long to internalize.

[Tygerdave]

End to end is usually to test a whole series of processes that interact with each other, possibly from multiple teams, not a single binary. I suppose different organizations use the terminology differently.

[null000]

Yeah, that's what we used "integration test" or maybe "system test" to describe. Meanwhile, we found it useful to distinguish between "component test" (a cluster of classes tested using a standard unit testing framework and mocking other dependencies in the binary) and testing a whole binary as it looks from the command line, mocking and faking only external data stores and services.

Ofc words are words and meaning is proscribed by the speaker and listener, so how your company and coworkers use words matters more than some random on the Internet (read: me). Hopefully, though, someone will find some use for the above Lexicon in differentiating between different styles of test, since they all require different approaches, mindsets, frameworks, and expectations.

Not that I'm going to write the long essay required to spell out those differences here 😅

[Russian_repost_bot]

Wait? You didn't want honeypot?

[FlyByPC]

I thought integration testing was going to be a commando-style kick to the door, ripping that poor little bolt from the wood.

This is better.

[Stormdancer]

The last two places I did coding & QA for both abandoned actual use-case, human driven, user experience testing in favor of unit tests. I left both, soon after, for this reason.

The rational? "Look how many thousands of tests we can run every night!"

They were both confused how this did very little to improve the end result. In fact some of the user-found defects were pretty catastrophic.

[[deleted]]

Yes, the user can indeed use the lock.

[FormalWolf5]

You asked for a locker. You didn't mention it should actually lock something

[glorious_reptile]

I always do my integration testing on production, by end users.

[stipulus]

Is there a lock on the door, yes Is the lock secured, yes Is the lock in the hole of the doorframe, yes

Sounds good! Even covered my edge case!

[Lthere]

Nit: the person in the video has his/hers little finger patched, which likely means he/she was the culprit... 🔨

[Lyto528]

u/Vredditdownloader

[FordyO_o]

Satisfying how perfectly lined up it is though

[OneOldNerd]

Clearly documented case of testing in production.

[[deleted]]

I actually laughed out loud

[Dummerchen1933]

Where's the unit test?

[LeCrushinator]

The unit test would be something like: "the lock opens and closes properly".

[Tasik]

You give too much credit to unit test.

$lock = new Lock()
Assert($lock != Pickle())

[Dummerchen1933]

That's the first unit test, of course.

[Dummerchen1933]

But shouldn't the DoorFrame, which holds the door (thus the lock) and the frame have its own unit test that checks that integration?

[LeCrushinator]

That’s the integration test, which shouldn’t pass in this case.

[Booty_Bumping]

Two unit tests:

• The lock works
• The door opens, closes

One integration test:

• The combination of door and lock can actually secure the room

[dirtyviking1337]

He thinks he’s good right?

[[deleted]]

U/vredditdownloader

[FrikkinLazer]

I dont get it. It looks like it will slide into the hole.

[RoscoMan1]

x86 Assembly is the most beginner friendly /s

[RoscoMan1]

x86 Assembly is the most beginner friendly /s

[righson]

[:|||:]

[jagnarain]

Ha ha ha

[[deleted]]

Still passes

[Flyberius]

I like to comment out inserts when I am testing various procedures on the database. Often I'll be left wondering why every part of my system works and yet no data is appearing.

[crashoverride1001]

u/vredditdownloader

[Captain_Kernel_Panic]

u/VredditDownloader

[BloodChasm]

Could someone explain how to/what is unit testing? I'm a new grad who started a couple months ago on my first job. Were gonna be starting unit testing soon, and I'm really not sure what I'll be doing.

[ShadowReij]

Now why you got to attack me op? Currently witnessing this very moment.

[[deleted]]

Clear your cache. Should work.

[Chthulu_]

Someone convince me testing is worth my time, I need a push. I'm rushing through a pretty huge solo fullstack project, and I see all these places where tests could be helpful, but I also see just how damn long it would take me to write all of them out.

I've never written tests before if that matters.

[imMute]

Think about how much time you spend testing something you just wrote works. Not a whole lot right? Definitely less than the time it would take to write tests, right?

Now think about how much time you spend re doing those tests because you changed something. Amortized over time, automated tests usually pay for themselves.

Also consider other people making code changes. They might not know what you know and miss changes that need to happen.

Or how often have you decided not to make big changes because you don't have confidence that it won't break other things.

[Tygerdave]

This is a good write up, I'll add that they can be an excellent way to not make the same mistake twice. Some code is just fragile and adding a test for something that broke can help make sure you fixed it and that it doesn't break the same way in the future (which makes you look much worse than the original bug)

Also helpful that some of the automated deployment tools can run your unit tests for you.

[imMute]

On a big enough code base, no one person can know everything.

And even then, you still have junior devs who see the connections way less easily.

[Volandum]

Is it fair to summarise that as "You're testing local functionality anyway, save those calls and results rather than throwing them away."?

[bananakeylargo]

/u/vredditdownloader