Detox v20 Breaking Changes: Planning

[d4vidi]

Following is a dynamic list of the things we'd like to introduce as breaking changes in our upcoming major release (Detox v20).
I've set this up as a discussion, so as to create a place for maintainers to talk about that list alongside the ability to update it accordingly.

Detox v20 Planned Breaking Changes:

• Jest w/ jasmine
• Drop the default specs values:
  • mocha: Detox interfers with .mocharc's "spec" property when Detox "specs" is not defined #3076
  • Jest CLI options such as --onlyChanged don’t work #2901
• Drop mocha integration proposal: ⚠️ Dropping Mocha support in Detox 20 ⚠️  #3193
• Drop skipLegacyWorkersInjection: feat(config): skipLegacyWorkersInjection #2872
• Usage of ActivityTestRule instead of ActivityScenarioRule
• Adding genymotion artifactory to apps' repositories list in build.gradle (instead of bundling the lib inside Detox' aar)
• Genymotion official support?
• Retire device.relaunch()
• Retire ios.none (replaced with behavior=manual, which is technically identical, yet easier to maintain).

[noomorph]

Okay, so here it depends on how promptly you want to break, @d4vidi. If I we give extra 1-2 months towards Detox 19, I'd vote for also including the new globalSetup/globalTeardown integration with jest-circus.

[d4vidi]

It's not up to me, but something we'd have to decide together. We do need to take into account that the next Q is not going to be our most effective one.

[noomorph]

Detox 19 should remove skipLegacyWorkersInjection flag added in #2872. Only the new behavior will be supported.

Also, I am considering removing -w, --workers in favor of -w, --maxWorkers natively supported by Jest.

[noomorph]

I suggest passing through environment variables such as DETOX_CONFIGURATION, DETOX_LOGLEVEL, etc. for both Mocha and Jest, to unify the behavior and make it easier to access certain CLI settings in runtime.

I've been thinking about this opportunity for a while, and this is one of steps to alleviate getting back to Mocha's first-class support.

[d4vidi]

Remove support in old configuration scheme? I think it's a little confusing while we allow for both generations of schemes. For example: type field in configuration ultimately overrides the type field of the associated device -- a mistake that is not an error and therefore hard to detect.
@noomorph

[d4vidi]

@noomorph this is a bit ground-shaking, but hear me out:
deprecate the detox build option in the Detox CLI.

Over the course of the project's lifetime, the separation between test and build was often a source of confusion, due to:

1. The very fact that there are two different phases before executing the tests, and the fact that test depends on build ( = unnecessary usage complexity).
2. The usage of the various arguments. Except for --configuration, all known args are not applicable to detox build, although similar to detox test.

My suggestion:
detox test builds by default, with a support for an optional opt-out arg of --no-build.

[noomorph]

@d4vidi your suggestion sounds sound. Moreover, if we develop a fair subsystem of scripts (prebuild, postbuild, pretest, posttest), that indeed might work.

[noomorph]

• ⚠️ Dropping Mocha support in Detox 20 ⚠️  #3193

[d4vidi]

Android emulators (google): Always run in read-only mode (even for a single instance)

[d4vidi]

Additional suggestion: iOS simulators to run non-headless by default @asafkorem