Stepping down as Mockito maintainer after 10 years

https://github.com/mockito/mockito/issues/3777

116•saikatsg•2h ago

Comments

senko•1h ago

For those, like me, who haven't heard of it: Mockito is the "most popular mocking framework for Java".

ronnier•1h ago

It’s taken years off of my life dealing with the test mess people have made with it.

schumpeter•47m ago

It also translates to “small booger”, in Spanish, which always made me question who thought the name was a good idea over there.

Freak_NL•40m ago

Why? Every name you pick is likely to be weird in one language or another. Mockito does one thing well as a name, and that is hinting strongly at what it is (a mocking library).

kace91•26m ago

>is likely to be weird in one language or another.

But this name is weird in the specific language it’s imitating (both the -ito termination for diminutives and the drink on which I assumed the name is based are Spanish).

marinesebastian•29m ago

Actually, no. "small booger" would be _moquito_ in spanish.

schumpeter•3m ago

Fair. The spelling is off, but the pronunciation is the same.

didip•59m ago

As someone who is not in the Java world, why does Java need a mocking library? Interface based polymorphism is not enough?

voidhorse•57m ago

Arguably it doesn't. Mocking is over used and you should just use a real implementation or distributor provided fake whenever possible.

totallykvothe•55m ago

Mockito allows one to write mocks in tests for code that doesn't use dependency injection and isn't properly testable in any other way.

On the one hand, you should just design things to be testable from the start. On the other... I'm already working in this codebase with 20 years of legacy untestable design...

deepsun•26m ago

Google API libraries mark every class as "final" so it's not trivial to mock-extend it for tests. But third-party IO is exactly the thing you'd want to mock.

Probably because they zealously followed "Effective Java" book.

gleenn•55m ago

There are many cases where you don't control the library code your code depends on that you want to test. Also, the FactoryFactoryFactory patterns can be quite cumbersome and simply mocking out something makes for a far simpler test. There are likely more common cases.

eoskx•52m ago

As someone who has been out of Java for close to 10 years now, you certainly could do without Mockito, but you'd be writing a lot of boiler plate code repetitively. There's also the case of third-party libraries that you don't control and Mockito has decent facilities for working with those, especially when you're working with a codebase that isn't pure DI and interfaces.

marginalia_nu•51m ago

The point is to let you create mocks without having to go through the whole polymorphism rigmarole, without forcing classes to define a separate interface or anything like that.

krackers•50m ago

Mocks make it easy to record and assert on method invocations. Additionally spys (instance mocks) are really useful when you need to forward to the real method or rely on some state.

At the moment I can't see anything Mokckito gives that you technically couldn't implement yourself via subclassing and overriding, but it'd be a lot of boilerplate to proxy things and record the arguments.

sunnybeetroot•35m ago

Subclasing and overriding is not a good idea. There is no compilation failure if you forget to override a function which can lead to flakey tests at best and prod data impact at worst.

wmichelin•34m ago

your test environment should not have the credentials to write to prod data. yiiiiikes!

sunnybeetroot•30m ago

Credentials end up existing in prod because the person used Mochito and didn’t override the function for providing credentials :’c

tripple6•48m ago

Mockito uses declarative matching style of specifying what should be mocked. You don't need to implement or even stub all of interface methods since Mockito can do it itself. It may be extremely concise. For example, interfaces may have tens methods or even more, but only one method is needed (say, java.sql.ResultSet). And finally probably the most important thing, interaction with mocks is recorded and then can be verified if certain methods were invoked with certain arguments.

davnicwil•19m ago

because even supposing you have an interface for your thing under test (which you don't necessarily, nor do you necessarily want to have to) it lets you skip over having to do any fake implementations, have loads of variations of said fake implementations, have that code live somewhere, etc etc.

Instead your mocks are all just inline in the test code: ephemeral, basically declarative therefore readily readable & grokable without too much diversion, and easily changed.

A really good usecase for Java's 'Reflection' feature.

gleenn•58m ago

Sad to see an important project's core maintainer leave but their justification seems very understandable. It is sad so much of OSS is maintained by very few as they alluded to in the XKCD comment, an especially given they felt the JVM ecosystem was causing them pain with limited support or feedback possible. I think it is always a little irresponsible to cause a great deal of breakage and not be there to support those who you break downstream of your project.

krackers•56m ago

>Mockito 5 shipped a breaking change where its main artifact is now an agent. That's because starting JVM 22, the previous so-called "dynamic attachment of agents" is put behind a flag

Wouldn't this hold back enterprise adoption, the same way breaking changes meant that Java 8 was widely used for a long time?

njitbew•43m ago

I respect the maintainer's decision, but I don't understand the justification.

> but when it was communicated with Mockito I perceived it as "Mockito is holding the JVM ecosystem back by using dynamic attachment, please switch immediately and figure it out on your own".

Who did the communication? Why is dynamic attachment through a flag a problem, and what was the solution? Why is "enable a flag when running tests" not a satisfactory solution? Why do you even need a _dynamic_ agent; don't you know ahead of time exactly what agent you need when using Mockito?

> While I fully understand the reasons that developers enjoy the feature richness of Kotlin as a programming language, its underlying implementation has significant downsides for projects like Mockito. Quite frankly, it's not fun to deal with.

Why support Kotlin in the first place? If it's a pain to deal with, perhaps the Kotlin user base is better served by a Kotlin-specific mocking framework, maintained by people who enjoy working on those Kotlin-specific code paths?

moribvndvs•30m ago

Mockito was indeed a poor fit for Kotlin. MockK is the one. Except I suppose for shops that have projects that mix Java and Kotlin and already have a Mockito tests.

CodesInChaos•23m ago

What does Agent mean in this context? And what is "dynamic attachment of agents"?

LoganDark•13m ago

A JVM agent is able to instrument and modify running JVM applications. Stuff like debugging, hot patching, etc rely on this. You used to be able to tell the JVM to listen on a port where you could connect debuggers (agents) dynamically at runtime, but that was deemed a security issue so now you can only declare specific agents at launch time through command-line flags.

njitbew•11m ago

See https://openjdk.org/jeps/451: JEP 451: Prepare to Disallow the Dynamic Loading of Agents, which has a lot of background on the topic.

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