No permission when pulling screenshots

[graf-semmel]

Hi there.
I am using Screengrab to capture screenshots during ui tests.
Screengrab runs the ui test itself and tries to pull them at the end from the device. That works fine when I run the uiTestsWithScreenshots lane separately but not when it is called from the automated_test_emulator_run plugin.
I need to be adb root to be able to pull the screenshots.
When I set use_adb_root: true the lane crashes

[10:17:25]: Clearing phoneScreenshots within fastlane/metadata/android
[10:17:25]: $ /Users/tristan/Library/Android/sdk/platform-tools/adb -s emulator-5556 shell echo \$EXTERNAL_STORAGE
[10:17:25]: ▸ /sdcard
[10:17:25]: $ /Users/tristan/Library/Android/sdk/platform-tools/adb root
restarting adbd as root
timeout expired while waiting for device
[10:17:31]: Exit status: 1

Traceback (most recent call last):
	30: from /usr/local/bin/fastlane:23:in `<main>'
	29: from /usr/local/bin/fastlane:23:in `load'
	28: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/bin/fastlane:23:in `<top (required)>'
	27: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/cli_tools_distributor.rb:119:in `take_off'
	26: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/commands_generator.rb:41:in `start'
	25: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/commands_generator.rb:349:in `run'
	24: from /Library/Ruby/Gems/2.6.0/gems/commander-fastlane-4.4.6/lib/commander/delegates.rb:15:in `run!'
	23: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane_core/lib/fastlane_core/ui/fastlane_runner.rb:76:in `run!'
	22: from /Library/Ruby/Gems/2.6.0/gems/commander-fastlane-4.4.6/lib/commander/runner.rb:476:in `run_active_command'
	21: from /Library/Ruby/Gems/2.6.0/gems/commander-fastlane-4.4.6/lib/commander/command.rb:153:in `run'
	20: from /Library/Ruby/Gems/2.6.0/gems/commander-fastlane-4.4.6/lib/commander/command.rb:178:in `call'
	19: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/commands_generator.rb:108:in `block (2 levels) in run'
	18: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/command_line_handler.rb:36:in `handle'
	17: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/lane_manager.rb:56:in `cruise_lane'
	16: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/runner.rb:45:in `execute'
	15: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/runner.rb:45:in `chdir'
	14: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/runner.rb:49:in `block in execute'
	13: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/lane.rb:33:in `call'
	12: from Fastfile:15:in `block (2 levels) in parsing_binding'
	11: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/fast_file.rb:159:in `method_missing'
	10: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/runner.rb:157:in `trigger_action_by_name'
	 9: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/runner.rb:227:in `execute_action'
	 8: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/runner.rb:227:in `chdir'
	 7: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/runner.rb:253:in `block in execute_action'
	 6: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/actions/actions_helper.rb:50:in `execute_action'
	 5: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/runner.rb:261:in `block (2 levels) in execute_action'
	 4: from /Library/Ruby/Gems/2.6.0/gems/fastlane-plugin-automated_test_emulator_run-1.6.0/lib/fastlane/plugin/automated_test_emulator_run/actions/automated_test_emulator_run_action.rb:185:in `run'
	 3: from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/forwardable.rb:230:in `sh'
	 2: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane/lib/fastlane/helper/sh_helper.rb:80:in `sh_control_output'
	 1: from /Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane_core/lib/fastlane_core/ui/ui.rb:17:in `method_missing'
/Library/Ruby/Gems/2.6.0/gems/fastlane-2.142.0/fastlane_core/lib/fastlane_core/ui/interface.rb:153:in `shell_error!': [!] Exit status of command 'fastlane uiTestsWithScreenshots' was 1 instead of 0. (FastlaneCore::Interface::FastlaneShellError)

when set to use_adb_root: false there is no crash but I get a permission denied error when pulling the screenshot folder.
Running the automated_test_emulator_run plugin as adb root might solve the problem. What do you think about it?

automated_test_emulator_run(
    AVD_setup_path: "fastlane/avd_api29_setup.json",
    AVD_recreate_new: false,
    AVD_clean_after: false,
    shell_task: "fastlane uiTestsWithScreenshots"
)

lane :uiTestsWithScreenshots do
    gradle(task: "assembleDebug assembleAndroidTest")
    screengrab(
        locales: ['en-US'],
        ending_locale: 'en-US',
        use_adb_root: true,
        clear_previous_screenshots: true,
        app_package_name: "com.littlepay.android.sdk.sample",
        app_apk_path: "sample/build/outputs/apk/debug/sample-debug.apk",
        tests_apk_path: "sample/build/outputs/apk/androidTest/debug/sample-debug-androidTest.apk"
    )
end