Firefox for iOS
Skip this if you are not working on Firefox for iOS and FxA.
You can test sync locally in Firefox iOS using the XCode simulator. Follow the steps at github.com/mozilla/firefox-ios and setup firefox-ios build locally. Currently there is no way to dynamically switch servers in Firefox for iOS, to use local servers you need to run the script below:
FIREFOX_IOS_HOME=<path_to_firefox_ios_project> npm run config-fxios
After the script you need to rebuild firefox-ios.
The following technique works with any Android application and can also be used for Firefox for Android.
Simply forward the following ports from the host machine to the Android device:
npm run adb-reverse
adb reverse tcp:3030 tcp:3030 # Content server
adb reverse tcp:9000 tcp:9000 # Auth server
adb reverse tcp:9010 tcp:9010 # OAuth server
adb reverse tcp:1111 tcp:1111 # Profile server
adb reverse tcp:5000 tcp:5000 # Sync server
yarn start and get to work!