1517881 - Move us onto more modern testing tool

Status: RESOLVED WONTFIX

(Taskcluster :: Services, enhancement)

Description

[Brian Stack [:bstack]]

jest seems like a good option. It does some nice things with output during testing, etc. Also has ways of integrating with monorepo nicely.

Comment 1

[Brian Stack [:bstack]]

Do you have an opinion on this, John? Owlish has had good experience with jest but otherwise I don't have a lot of direct experience.

Mostly this is motivated by better integration with monorepo stuff, speed/consistency of tests, and reporting concerns.

Comment 2

[John Ford [:jhford] CET/CEST Berlin Time]

It looks like a nice framework, though I haven't really gotten deep into it. My only concern here is that we have working tests with Mocha right now, and depending on how much work it is to port them to jest, it might not be worthwhile for existing tests. Basically, it feels like adding another variable when we've already got a decent amount of churn happening.

That said, I have no strong attachment to Mocha and if Jest is better, then let's do it! Before we decide to stop using Sinon though, we should play around with the Jest mocking/spying/stubbing stuff.

What about converting a smaller library or service to Jest and see how it goes before we make a call?

Comment 3

[Brian Stack [:bstack]]

Basically, it feels like adding another variable when we've already got a decent amount of churn happening.

Yeah, I definitely feel this. The only reason I would want to do it sooner than later is that I want code coverage and the way we would do that with mocha is different than with jest so I'd like to avoid doing it twice.

What about converting a smaller library or service to Jest and see how it goes before we make a call?

https://github.com/taskcluster/taskcluster/compare/jester is a WIP that ports a handful of our smaller libraries. They actually have an automated tool for converting 90% of cases.

Comment 4

[Brian Stack [:bstack]]

Meh, I added coverage separately and mocha is more than good enough.