[randomdata]

> The idea that unit testing should be the default go to test I find to be horrifying.

Kent Beck, who invented the term unit test, was quite clear that a unit test is a test that exists independent of other tests. In practice, this means that a unit test won't break other tests.

I am not sure why you would want anything other than unit tests? Surely everyone agrees that one test being able to break another test is a bad practice that will turn your life into a nightmare?

I expect we find all of these nonsensical definitions for unit testing appearing these days because nobody is writing anything other than unit tests anymore, and therefore the term has lost all meaning. Maybe it's simply time to just drop it from our lexicon instead of desperately grasping at straws to redefine it?

> It seems to be tied up with some sort of idea that unit testability/DI just makes code inherently better.

DI does not make testing or code better if used without purpose (and will probably make it worse), but in my experience when a test will genuinely benefit from DI, so too will the actual code down the line as requirements change. Testing can be a pretty good place for you to discover where it is likely that DI will be beneficial to your codebase.

> The idea that test realism might actually matter more than test speed.

Beck has also been abundantly clear that unit tests should not resort to mocking, or similar, to the greatest extent that is reasonable (testing for a case of hardware failure might be place to simulate a failure condition rather than actually damaging your hardware). "Realism" is inherit to unit tests. Whatever it is you are talking about, it is certainly not unit testing.

It seems it isn't anything... other than yet another contrived attempt to try and find new life for the term that really should just go out to pasture. It served its purpose of rallying developers around the idea of individual tests being independent of each other – something that wasn't always a given. But I think we're all on the same page now.

[RaftPeople]

> Kent Beck, who invented the term unit test, was quite clear that a unit test is a test that exists independent of other tests

Kent Beck didn't invent the term "unit test", it's been used since the 70's (at minimum).

> I am not sure why you would want anything other than unit tests?

The reason is to produce higher quality code than if you rely on unit tests only. Generally, unit tests catch a minority of bugs, other tests like end to end testing help catch the remainder.

[randomdata]

> other tests like end to end testing help catch the remainder.

End-to-end tests are unit tests, generally speaking. Something end-to-end can be captured within a unit. The divide you are trying to invent doesn't exist, and, frankly, is nonsensical.

[RaftPeople]

> End-to-end tests are unit tests, generally speaking.

Generally, in the software industry, those terms are not considered the same thing, they are at opposite ends of a spectrum. Unit tests are testing more isolated/individual functionality while the end to end test is testing an entire business flow.

Here's an example of one end to end test (with validations happening at each step):

1-System A sends Inventory availability to system B

2-The purchasing dept enters a PO into system B

3-System B sends the PO to system A

4-System A assigns the PO to a Distribution Center for fulfillment

5-System A fulfills the order

6-System A sends the ASN and Invoice to system B

7-System B users process the PO receipt

8-System B users perform three way match on PO, Receipt and Invoice documents

[randomdata]

> Here's an example of one end to end test

Bad example, perhaps, but that's also a unit test[1]. Step 8 is dependent on the state of step 1, and everything else in between, so it cannot be reduced any further (at last not without doing stupid things). That is your minimum viable unit; the individual, isolated functionality.

[1] At least so long as you don't do something that couples it with other tests, like modifying a shared database in a way that that will leave another test in an unpredictable state. But I think we have all come to agree that you should never do that – going back to the reality that the term unit test serves no purpose anymore. For all intents and purposes, all tests now written are unit tests.

[RaftPeople]

Every step updates shared databases (frequently plural). In the case of the fulfillment step, the following systems+databases were involved: ERP, WMS, Shipping.

Typically, in end to end testing, tests are run within the same shared QA system and are semi-isolated based on choice of specific data (e.g. customers, products, orders, vendors, etc.). If this test causes a different test to fail, or vice-versa, then you have found a bug.

If we call that entire sequence of steps a "unit" test, would you start with testing the entire sequence of steps, or would you recommend testing the individual steps first?

And if we did test the individual steps first, we would give that testing a different name? Like maybe "sub-unit" testing?

[randomdata]

> Every step updates shared databases (frequently plural).

That's fine. It all happens within a single unit. A unit should mutate shared state within the unit. Testing would be pretty much useless without.

> If we call that entire sequence of steps a "unit" test, would you start with testing the entire sequence of steps, or would you recommend testing the individual steps first?

For all intents and purposes, you can't test the individual steps. All subsequent steps are dependent on the change in inventory state in step 1. And the product of step one is undoubtedly internal state, so there is no way for the test to observe the state change in isolation (unless you do something stupid). You have to carry out the subsequent steps to be able to infer that the inventory was, in fact, updated appropriately.

After all, the whole reason you are testing those steps together is because you recognize that they represent a single instance of functionality. You don't really get to choose (unless you choose to do something stupid, I suppose).

> And if we did test the individual steps first, we would give that testing a different name?

If the individual steps can be tested individually (ignoring a case of you doing something stupid), it's not actually and end-to-end process, so your example would make no sense. Granted, we have already questioned if it is a bad example.

[MoreQARespect]

>Kent Beck, who invented the term unit test, was quite clear that a unit test is a test that exists independent of other tests

I vaguely remember him also complaining that there were too many conflicting definitions of unit tests.

Maybe that can be solved with another definition?

https://xkcd.com/927/

or maybe not.

I dont know many people who would describe a test that uses playwright and hits a database as a unit test just because it is self contained. If Kent Beck does then he has a highly personalized definition of the term that conflicts with its common usage.

The most common usage is, I think, an xUnit style test which interacts with an app's code API and mocks out, at a minimum, interactions with systems external to the app under test (e.g. database, API calls).

He may have coined the term but that does not mean he owns it. If I were him Id pick a different name for his idiosyncratic meaning than unit test - one that isnt overburdened with too much baggage already.

[randomdata]

> He may have coined the term but that does not mean he owns it.

Certainly not, but there is no redefinition that is anything more than gobbledygook. Look at the very definition you gave: That's not a unique or different way to write tests. It's not even a testing pattern in concept. That's just programming in general. It is not, for example, unusual for you to use an alternative database implementation (e.g. an in-memory database) during development where it is a suitable technical solution to a technical problem, even outside of an automated test environment. To frame it as some special unique kind of test is nonsensical.

If we can find a useful definition, by all means, but otherwise what's the point? There is no reason to desperately try to save it with meaningless words just because it is catchy.

[MoreQARespect]

The definition I gave is the one people use. Hate or love it youre not going to change it to encompass end to end tests and neither will Kent Beck. It's too embedded.

[randomdata]

> youre not going to change it

I might. I once called attention to the once prevailing definition of "microservices" also not saying anything. At the time I was treated like I had two heads, but sure enough now I see a sizeable portion (not all, yet...) of developers using the updated definition I suggested that actually communicates something. Word gets around.

Granted, in that case there was a better definition for people to latch onto. In this case, I see no use for the term 'unit test' at all. Practically speaking, all tests people write today are unit tests. 'Unit' adds no additional information that isn't already implied in 'test' alone and I cannot find anything within the realm of testing that needs additional differentiation not already captured by another term.

If nothing changes, so what? I couldn't care less about what someone else thinks. Calling attention to people parroting terms that are meaningless is entirely for my own amusement, not some bizarre effort to try and change someone else. That would be plain weird.