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by jasonwocky 4130 days ago
Depends on the use case. For automated testing, if I'm developing service A, then locally I'd usually I'd want to stub B & C with something like Mountebank (http://www.mbtest.org/) (though I've never used it to do a post-back as you describe...not sure if it supports that out of the box).

If I just wanted to poke around a running system to see how things interact manually, yeah I'd run everything locally. Probably using Docker images for each dependency service and Vagrant to manage the suite of those images, to preserve my sanity.
2 comments
AndrewHampton 4130 days ago
Yeah, this is pretty much what we do. We only use test suites for the backend apps which only expose an API. They just stub out calls to other services.

However, our front end apps is where we're running into trouble. The people on the front end want to run through everything in their browser to make sure everything works and looks good.

We use docker and fig (now docker-compose) to run all our apps. So we've been talking about using compose's new external_links feature to link each app together.

I hadn't heard of moutebank though, so thanks for the link!

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tekacs 4130 days ago
Mountebank/mocking is a great solution when your components are too big to spin up new ones for 'free'.

It's exactly because Docker-based components end up so big that it seems hard to believe in the viability of that approach to microservices though. :/

It's a great stopgap/migratory step, though.

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bbyars 4128 days ago
I think some level of integration testing is always a good thing, but spinning up all dependent services just so you can test yours leads to all kinds of problems, even in microservices. You end up with cascading dependencies.

At scale, some level of stubbing is required to test.

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tekacs 4122 days ago
Agreed.

We _partially_ solve this problem by letting you run a dev cluster that you can use for services which are awkward to run locally, but stubbing/mocking definitely has a place in automated testing, certainly.

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bbyars 4128 days ago
mountebank could support that through stub resolver injection (http://www.mbtest.org/docs/api/injection). Basically, in addition to returning a response, you can inject some javascript that would call back after some time. Tricky, but possible.
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