meson: determine running tests as root - testing

Question

In tests for ping from iputils certain tests should fail for non-root but pass for root. Thus I need a detection whether user running tests is root or not. Current code:
run_as_root = false
r = run_command('id', '-u')
if r.stdout().strip().to_int() == 0
message('running as root')
run_as_root = true
else
message('running as normal user')
endif
...
test(name, cmd, args : args, should_fail : not run_as_root)
is not working, because test is done during build phase:
$ meson builddir
The Meson build system
Version: 0.59.4
...
Program xsltproc found: YES (/usr/bin/xsltproc)
Message: running as normal user
and not for running tests because root user is not properly detected:
# cd builddir/ && meson test
[21/21] Linking target ninfod/ninfod
1/36 arping -V OK 0.03s
...
32/36 ping -c1 -i0.001 127.0.0.1 UNEXPECTEDPASS 0.02s
>>> ./builddir/ping/ping -c1 -i0.001 127.0.0.1
33/36 ping -c1 -i0.001 __1 UNEXPECTEDPASS 0.02s
What to do to evaluate user when running tests?

Answer 1

This is really a case for skipping rather than expected failure. It would be easy to wrap your tests in a small shell or python script that checks the effective UID and returns the magic exit code 77 (which meson interprets as skip)
Something like:
#!/bin/bash
if [ "$(id -u)" -ne 0 ]; then
echo "User does not have root, cannot run"
exit 77
fi
exec "$#"
This will cause meson test to return a status of SKIP if the tests are not run as root.