what do you actually want to decline: the test, or the job?

Does this answer your question? How to deal with "too much" workload for a take home assignment?

@virolino the test.

Why do you not already have a lab environment for your area of expertise? Thats a bit of a red flag.

@Kilisi: a while ago I was in a similar situation, applied for a C++ backend developer position, got a test, turned out the test was for a windows gui application. Got nothing much to do with what the position was about. I don't even have windows, let alone know how to write GUI stuff. Declined the job with "I was not aware that linux backend servers means windows gui programming". Might be in that direction here too. Generally I think at least for senior level positions doing such tests should make you think twice to work there...

@PlasmaHH Just so you know, that wasn't a complete one-off. We use Linux backends to run Java code to control a Windows-based GUI as well...so yeah, it's a thing.

@Kilisi why do you find software engineers without a ready-to-go "lab environment" a red flag? Is it expected from developers to make their hobby into their job or vice versa?

Does this answer your question? How much work would be a suspicious amount to request for an interview process? How can I politely decline the offer?

@Kilisi OP could already have a lab environment ready at home, and still have to setup another one if the given task requires specific libraries (or versions of it), connections and configurations that are different to what you would expect in a "common" dev environment.

@JoshPart Even starting from scratch, it's difficult to image any base environment requiring 3 hours to setup. Smells like a strong indicator OP is not currently ready for this environment at this stage of their career, and is probably learning as they go instead of already knowing it. This is likely one of the reasons this test exists - weed out those who may have inflated their resume to make the interview.

@CodeCaster It's a pretty reasonable expectation to assume a prospecting Software Engineer be capable of setting up a development environment for the language they are being hired to develop in. If it is difficult to setup that environment for an individual, it likely highlights a lack of skills in that specific language domain (and it's tooling).

It's worth understanding that an employer sending you home with a test has no incentive to make you feel fully qualified. Why anyone would trust their numbers is beyond me.

@SnakeDoc that was not the claim, it was that one should already have one.

@CodeCaster if the OP is interviewing, then yes having a lab environment would just be basic prep. I have more than one and I'm neither a dev nor interviewing.

@Kilisi a (potential) employer should provide adequate tooling, be it in the form of preinstalled hardware, an online development environment, images or VMs, scripts, and in the last case documentation for how to set one up. Given the many different environments and configurations that can exist within one company, it would be wasteful to be ready for anything, at home. I just find your "red flag" remark kind of weird. And that's coming from a developer who has multiple machines capable of building for various languages and environments, at home.

Perhaps they should give them a laptop prebuilt and some donuts as well?