why do we copy over utils for test?

[npeltier]

In some recent work, i counted at least 3 copies of utils.js in test code i had to amend at the same time i was changing utils. I could do diff and try to understand why, but i figured i could ask here :p

• why do we copy it over every time?
• if we need a utils mock, why don't we create only one?

[mokimo]

To ensure we are on the same page, you refer to something such as this?

Makes sense to mock it once and re-use that. We haven't built a lot of helpers/general mocks for unit tests - there are only a few here: https://github.com/adobecom/milo/tree/main/test/helpers

So to answer your question, my best guess is that no one started a re-usable mock and thus things have just been copied over.

I 👍 your suggestion to creating one

[npeltier]

yes, didn't see that one as i was searching for createTag usages, but:

/test/blocks/instagram/mocks/embed-utils.js
/test/blocks/marketo/mocks/marketo-utils.js
/test/blocks/slideshare/mocks/utils.js
/tools/loc/utils.js

also. Some of those usages look "assumed" by creators so first my discussion on being really sure there was no value in having your super specific mock

[mokimo]

There might be scenario's where you want to mock something super specific to get into a special code path... the norm case should be pretty deterministic though - such as createIntersectionObserver just immediately firing

[mokimo]

Plus: Once you mock the utils, you need to mock EVERY function that is being used - which would be a lot easier to set up once and then be consumable by a bunch of unit tests