testsuite: add sdmon test script

Problem: there is no test coverage for the sdmon module.

Add a new sharness script.

t/Makefile.am

@@ -197,6 +197,7 @@ TESTSCRIPTS = \
 	t2409-sdexec.t \
 	t2410-sdexec-memlimit.t \
 	t2411-sdexec-job.t \
+	t2412-sdmon.t \
 	t2500-job-attach.t \
 	t2501-job-status.t \
 	t2600-job-shell-rcalc.t \

t/t2412-sdmon.t

@@ -0,0 +1,125 @@
+#!/bin/sh
+# ci=system
+
+test_description='Test flux systemd monitoring'
+
+. $(dirname $0)/sharness.sh
+
+if ! flux version | grep systemd; then
+	skip_all="flux was not built with systemd"
+	test_done
+fi
+if ! systemctl --user show --property Version; then
+	skip_all="user systemd is not running"
+	test_done
+fi
+if ! busctl --user status >/dev/null; then
+	skip_all="user dbus is not running"
+	test_done
+fi
+if ! busctl status >/dev/null; then
+	skip_all="system dbus is not running"
+	test_done
+fi
+
+test_under_flux 1 minimal
+
+flux setattr log-stderr-level 1
+
+# Usage: start test unit NAME (without service suffix)
+start_test_unit() {
+	local sleep=$(which sleep)
+	flux exec \
+	    --service sdexec \
+	    --setopt SDEXEC_NAME="$1.service" \
+	    $sleep 3600 &
+}
+# Usage: stop_test_unit NAME (without service suffix)
+stop_test_unit() {
+	systemctl --user stop $1
+}
+# Usage: wait_for_none MAXSEC
+wait_for_none() {
+	local retry=$(($1*10))
+	while ! flux module stats sdmon | jq -e ".units == []"; do
+	    sleep 0.1
+	    retry=$(($retry-1))
+	    test $retry -gt 0 || exit 1
+	done
+}
+# Usage: wait_for_some MAXSEC
+wait_for_some() {
+	local retry=$(($1*10))
+	while flux module stats sdmon | jq -e ".units == []"; do
+	    sleep 0.1
+	    retry=$(($retry-1))
+	    test $retry -gt 0 || exit 1
+	done
+}
+
+groups="flux python ${SHARNESS_TEST_SRCDIR}/scripts/groups.py"
+
+test_expect_success 'load sdbus,sdexec modules' '
+	flux module load --name sdbus-sys sdbus system &&
+	flux module load sdbus &&
+	flux module load sdexec
+'
+test_expect_success 'load sdmon module' '
+	flux module load sdmon
+'
+test_expect_success 'make sure residual test units are not running' '
+	stop_test_unit shell-t2412 || true &&
+	stop_test_unit imp-shell-t2412 || true
+'
+test_expect_success 'wait for it to join the sdmon.online group' '
+	run_timeout 30 $groups waitfor --count=1 sdmon.online
+'
+test_expect_success 'module stats units array is empty' '
+	flux module stats sdmon | jq -e ".units == []"
+'
+test_expect_success 'run a systemd unit with imp-shell- prefix' '
+	start_test_unit imp-shell-t2412
+'
+test_expect_success 'wait for module stats to show test unit' '
+	wait_for_some 30
+'
+test_expect_success 'remove sdmon module' '
+	flux module remove sdmon
+'
+# removing the module triggers a disconnect that causes a group leave
+test_expect_success 'wait for it to leave the sdmon.online group' '
+	run_timeout 30 $groups waitfor --count=0 sdmon.online
+'
+test_expect_success 'load sdmon module' '
+	flux module load sdmon
+'
+test_expect_success 'wait for module stats to show test unit' '
+	wait_for_some 30
+'
+test_expect_success 'stop the unit' '
+	stop_test_unit imp-shell-t2412
+'
+test_expect_success 'wait for sdmon to join the sdmon.online group' '
+	run_timeout 30 $groups waitfor --count=1 sdmon.online
+'
+test_expect_success 'run a systemd unit with shell- prefix' '
+	start_test_unit shell-t2412
+'
+test_expect_success 'wait for module stats to show test unit' '
+	wait_for_some 30
+'
+test_expect_success 'stop the unit' '
+	stop_test_unit shell-t2412
+'
+test_expect_success 'wait for module stats stop showing test unit' '
+	wait_for_none 30
+'
+test_expect_success 'remove sdmon module' '
+	flux module remove sdmon
+'
+test_expect_success 'remove sdexec,sdbus modules' '
+	flux module remove sdexec &&
+	flux module remove sdbus &&
+	flux module remove sdbus-sys
+'
+test_done