Docs: Jest usage

[DanielMSchmidt]

Heavily inspired by the solution of @AlanFoster and with the help of @levito

[chirag04]

I like how you can define jest config in your package.json so you don't have to pass in --setupTestFrameworkScriptFile. Just making a note. either way is fine.

"jest": {
    "bail": true,
    "setupTestFrameworkScriptFile": "<rootDir>/jest/setup.js"
  },

[DanielMSchmidt]

This is intentional because we wanted to make sure that they run side by side with your normal unit tests

[chirag04]

sure. either way is fine. you can push that logic in setup file too: https://github.com/grabbou/react-native-detox-example/blob/master/jest/setup.js#L10-L14

[rotemmiz]

I would add a note re Detox that it exports expect, waitFor, element and by, so Jest users might find themselves using a different expect object implicitly.

[rotemmiz]

BTW, we plan on adding another detox.init flavour/flag that will not export all that into globals, and users would need to explicitly import it. It would make lots of sense for Jest.

That might be an AWESOME opportunity for a PR (anyone? hint hint...)

[DanielMSchmidt]

@rotemmiz Noted the exposure of expect and so on
@chirag04 Thanks for the note, but this was intentional to have test run side by side with the unit tests

[rotemmiz]

Detox exposes it's primitives (expect, device, ...) globally, it will override Jest's global expect object.

[DanielMSchmidt]

@rotemmiz I will merge this, implemented your wish. Feel free to edit and improve 👍