Test "ubuntu-core-18-64:tests/core/snapd-refresh-vs-services-reboots " flaky

[Michael Vogt]

The test fails with:
"""
...
2021-10-27T15:03:37.8827278Z ##[error]2021-10-27 15:03:37 Error executing google:ubuntu-core-18-64:tests/core/snapd-refresh-vs-services-reboots (oct271439-116823) :
2021-10-27T15:03:37.8834557Z -----
2021-10-27T15:03:37.8835379Z + os.query is-pc-amd64
2021-10-27T15:03:37.8836101Z + '[' 0 = 0 ']'
2021-10-27T15:03:37.8837121Z + snap pack test-snapd-svc-flip-flop --filename=app.snap
2021-10-27T15:03:37.8838023Z built: app.snap
2021-10-27T15:03:37.8838779Z + snap install --dangerous app.snap
2021-10-27T15:03:37.8839521Z error: cannot perform the following tasks:
2021-10-27T15:03:37.8842619Z - Start snap "test-snapd-svc-flip-flop" (unset) services ([start snap.test-snapd-svc-flip-flop.svc1.service] failed with exit status 1: A dependency job for snap.test-snapd-svc-flip-flop.svc1.service failed. See 'journalctl -xe' for details.
"""

Unfortunately we don't have the "journalctl -xe" debug log.

[Michael Vogt (mvo)]

A similar failure in:
"""
2021-10-28T06:53:12.0311316Z ##[error]2021-10-28 06:53:12 Error executing google:ubuntu-core-18-64:tests/main/snap-connections (oct280634-802489) :
2021-10-28T06:53:12.0343994Z -----
2021-10-28T06:53:12.0344534Z + snap connections
2021-10-28T06:53:12.0345351Z ++ wc -l
2021-10-28T06:53:12.0345907Z + initial_connections=0
2021-10-28T06:53:12.0346850Z + snap install test-snapd-content-slot
2021-10-28T06:53:12.0348329Z test-snapd-content-slot 1.0 from Test snaps (test-snaps-canonical) installed
2021-10-28T06:53:12.0350816Z + expected='content +- +test-snapd-content-slot:shared-content-slot +-'
2021-10-28T06:53:12.0352280Z + MATCH -- 'content +- +test-snapd-content-slot:shared-content-slot +-'
2021-10-28T06:53:12.0353515Z + snap connections test-snapd-content-slot
2021-10-28T06:53:12.0354486Z + MATCH 'error: cannot use --all with snap name'
2021-10-28T06:53:12.0355461Z + snap connections test-snapd-content-slot --all
2021-10-28T06:53:12.0356175Z + snap connections
2021-10-28T06:53:12.0356739Z ++ wc -l
2021-10-28T06:53:12.0357113Z + test 0 = 0
2021-10-28T06:53:12.0361097Z + MATCH -- 'content +- +test-snapd-content-slot:shared-content-slot +-'
2021-10-28T06:53:12.0362314Z + snap connections --all
2021-10-28T06:53:12.0363198Z + snap install test-snapd-content-plug
2021-10-28T06:53:12.0364616Z test-snapd-content-plug 1.0 from Test snaps (test-snaps-canonical) installed
2021-10-28T06:53:12.0366555Z + expected='content\[mylib\] +test-snapd-content-plug:shared-content-plug +test-snapd-content-slot:shared-content-slot +-'
2021-10-28T06:53:12.0369113Z + MATCH 'content\[mylib\] +test-snapd-content-plug:shared-content-plug +test-snapd-content-slot:shared-content-slot +-'
2021-10-28T06:53:12.0370786Z + snap connections test-snapd-content-plug
2021-10-28T06:53:12.0372482Z + MATCH 'content\[mylib\] +test-snapd-content-plug:shared-content-plug +test-snapd-content-slot:shared-content-slot +-'
2021-10-28T06:53:12.0374070Z + snap connections test-snapd-content-slot
2021-10-28T06:53:12.0375426Z + /home/gopath/src/github.com/snapcore/snapd/tests/lib/tools/snaps-state install-local network-consumer
2021-10-28T06:53:12.0376617Z network-consumer 1.0 installed
2021-10-28T06:53:12.0377602Z + expected='network +network-consumer:network +:network +-'
2021-10-28T06:53:12.0378689Z + MATCH 'network +network-consumer:network +:network +-'
2021-10-28T06:53:12.0379633Z + snap connections network-consumer
2021-10-28T06:53:12.0380565Z + snap disconnect network-consumer:network
2021-10-28T06:53:12.0381551Z + expected='network +network-consumer:network +- +-'
2021-10-28T06:53:12.0382546Z + MATCH 'network +network-consumer:network +- +-'
2021-10-28T06:53:12.0383470Z + snap connections network-consumer
2021-10-28T06:53:12.0384830Z + /home/gopath/src/github.com/snapcore/snapd/tests/lib/tools/snaps-state install-local test-snapd-daemon-notify
2021-10-28T06:53:12.0385941Z error: cannot perform the following tasks:
2021-10-28T06:53:12.0410379Z - Start snap "test-snapd-daemon-notify" (unset) services (systemctl command [start snap.test-snapd-daemon-notify.notify.service] failed with exit status 1: A dependency job for snap.test-snapd-daemon-notify.notify.service f...

[Michael Vogt (mvo)]

Probably also related to https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1949089