Hey Stephan!
The file depending on meteor/mongo is /lib/collection/tags.js. I tried your code above, and unfortunately it didn’t work, same error as before. ChipInput imports ./Chip which imports chipTypes from ./index which then does:
import { Tag } from '/lib/collections/tags';
and tags.js starts out with:
import { Mongo } from 'meteor/mongo';
import { Class } from 'meteor/jagi:astronomy';
[...]
So I have no idea how to use proxyquire to follow this chain of imports and somehow stub meteor/mongo and any other Meteor packages it comes across.