Developing code for autoupdate_EndToEndTest is not easy:
it can only run in the lab, and being a server side test, need special permission to update. 
(https://sites.google.com/a/google.com/chromeos/for-team-members/infrastructure/chromeos-admin/push-to-prod)

As of today, it can not be tested until pushed.

I am able to run  locally thanks to David's note [https://docs.google.com/a/google.com/document/d/16leaxcmXMyb8_408xX8y7Jz5Wr5Ol8UpLHz-Dez20AY/edit?usp=sharing] and 2 CLs (468269 and 468270).

With a CROS entry in ...config.ini
devserver_dir: /usr/local/google/chromeos/src/platform/dev
devserver_user: chromeos-test
dev_server: http://100.115.219.136:8082

I can autoupdate with:
 test_that chromeos4-row8-rack10-host13.cros autoupdate_EndToEndTest  --args="name=paygen_au_canary
update_type=full
source_release=7978.66.0
target_release=9415.0.0
target_payload_uri=gs://chromeos-releases/canary-channel/sentry/9415.0.0/payloads/chromeos_9415.0.0_sentry_canary-channel_full_test.bin-664f61d70225fb3fa69b50a340cb00c5
SUITE=paygen_au_canary
source_payload_uri=gs://chromeos-releases/stable-channel/sentry/7978.66.0/payloads/chromeos_7978.66.0_sentry_stable-channel_full_test.bin-c12520f393d1172e85c10305788449ad
source_archive_uri=gs://chromeos-releases/stable-channel/sentry/7978.66.0" --ssh_private_key ~/.ssh/chromium ~/.ssh/testing_rsa