Ask HN: How should I test backing services that change frequently/break my code?

2 pointsayoubElk6y ago1 comments

Hi folks,

I'm working on a nodeJS application that acts as an API gateway for a mobile app being actively developed. This API gateway doesn't have any database, and formats/forwards requests to their appropriate services, then returns the expected response to the mobile app.

Obviously testing my code and mocking the backing services is necessary to make sure it works as expected. However those services are complex, aren't always stable, and sometimes changes are introduced to them that break the functionality of my API.

I'm wondering what the best testing/monitoring strategy would be here that would allow me to reduce bugs in my API, and in case of breaking changes be notified in order to make the necessary changes?

Thanks

1 comments

1 comments · 1 top-level

jimsmart6y ago

I am using a Github repo, linked to Travis CI - Travis can do cron/scheduled builds (daily works for me). On build failure, including if any of the tests fail, I receive notification.

Some of my tests use mocks, others hit live remote/third-party services. If anything external component/system changes, or is down, I get to know about it, and can decide what is the best action to take. Sometimes it’s nothing more than a network glitch / service outage, but sometimes endpoints change and/or return different data.

You should definitely consider setting up a monitoring service for your app’s live HTTP endpoint. There are online services that may provide the functionality you require, but otherwise it’s NBD to write your own.

It can be a good idea to run monitoring from a different network, e.g. a different host, from the office, from home (or all of these).

Bespoke monitoring code can sometimes/often leverage code that you already have in your tests. (Almost bringing us full circle, and back to CI)

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