Set the systemd user service to use "mixed" killmode, which lets waybar
stop its module scripts. This fixes issues where waybar blocks shutdown
until systemd sends a SIGKILL to waybar child processes.
This adds a "test.asserts" module that currently just provides a
convenient way to assert on the content of warnings. By default all
tests will assert that no warnings are given.
The current definition makes waybar wait for dbus.service, but that
never happens because dbus.service is started on demand by
dbus.socket.
Per systemd docs:
https://www.freedesktop.org/software/systemd/man/systemd.service.html#Implicit%20Dependencies
- Services with Type=dbus set automatically acquire dependencies of
type Requires= and After= on dbus.socket.
- Socket activated services are automatically ordered after their
activating .socket units via an automatic After= dependency.
Services also pull in all .socket units listed in Sockets= via
automatic Wants= and After= dependencies.
Removing Requisite/After makes the service properly start for me,
simply specifying Type=dbus is enough.
See #1370
