Otherwise the `terminate()` method sends SIGKILL rather quickly (~0.3s),
which then leaves a dangling scope on the host system, breaking further
test executions.
TEST-69 uses a Python wrapper around the systemd-nspawn call, which on
error calls the `spawn.terminate()` method. However, with no arguments
it will only use SIGHUP and SIGINT signals - this might leave a stuck
container around, causing fails if the test is run again. With `force=True`
SIGKILL is used as well (if necessary).
Those messages simply *feel* dated: "The system is going for suspend NOW!".
Let's say "The system will suspend|power off|hibernate|… now!" instead.
The exclamation mark is enough to show the urgency.
Also, the "the" seemed out of place. We're not talking about a specific reboot.
as it may take a bit longer on slower machines:
```
[ OK ] Reached target System Reboot.
Found cgroup2 on /sys/fs/cgroup/, full unified hierarchy
Failed to open watchdog device /dev/watchdog0, ignoring: No such file or directory
binfmt_misc is not mounted, not detaching entries.
Sending SIGTERM to remaining processes...
ERROR:test-shutdown:Timeout exceeded.
<pexpect.pty_spawn.spawn object at 0x7f3d4bcd20b0>
command: /systemd-meson-build/systemd-nspawn
<...snip...>
buffer (last 100 chars): 'mbinfmt_misc is not mounted, not detaching entries.\x1b[0m\r\nSending SIGTERM to remaining processes...\r\n'
before (last 100 chars): 'mbinfmt_misc is not mounted, not detaching entries.\x1b[0m\r\nSending SIGTERM to remaining processes...\r\n'
after: <class 'pexpect.exceptions.TIMEOUT'>
match: None
match_index: None
exitstatus: None
flag_eof: False
pid: 572528
child_fd: 5
closed: False
timeout: 30
delimiter: <class 'pexpect.exceptions.EOF'>
logfile: <_io.TextIOWrapper name='<stdout>' mode='w' encoding='utf-8'>
logfile_read: None
logfile_send: None
maxread: 2000
ignorecase: False
searchwindowsize: None
delaybeforesend: 0.05
delayafterclose: 0.1
delayafterterminate: 0.1
searcher: searcher_re:
0: re.compile('H login: ')
INFO:test-shutdown:killing child pid 572528
E: nspawn failed with exit code 1
```
Wraps nspawn to be able to use pexpect. The test logs in on the console
and runs screen. In one screen window it types in shutdown commands and
checks whether a wall message was sent to the other.
