test: add a test case that validates cgroup delegation

This test runs on the unified hierarchy, and ensures that cgroup
delegation works properly, i.e. writ access is granted and the requested
controllers are enabled.

test/TEST-19-DELEGATE/Makefile

@@ -0,0 +1,4 @@
+include ../Makefile.guess
+
+all setup clean run:
+	@basedir=../.. TEST_BASE_DIR=../ BUILD_DIR=$(BUILD_DIR) ./test.sh --$@

test/TEST-19-DELEGATE/test.sh

@@ -0,0 +1,43 @@
+#!/bin/bash
+# -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
+# ex: ts=8 sw=4 sts=4 et filetype=sh
+set -e
+TEST_DESCRIPTION="test cgroup delegation in the unifier hierarchy"
+TEST_NO_NSPAWN=1
+
+. $TEST_BASE_DIR/test-functions
+QEMU_TIMEOUT=180
+UNIFIED_CGROUP_HIERARCHY=yes
+
+test_setup() {
+    create_empty_image
+    mkdir -p $TESTDIR/root
+    mount ${LOOPDEV}p1 $TESTDIR/root
+
+    (
+        LOG_LEVEL=5
+        eval $(udevadm info --export --query=env --name=${LOOPDEV}p2)
+
+        setup_basic_environment
+
+        # setup the testsuite service
+        cat >$initdir/etc/systemd/system/testsuite.service <<EOF
+[Unit]
+Description=Testsuite service
+
+[Service]
+ExecStart=/bin/bash -x /testsuite.sh
+Type=oneshot
+StandardOutput=tty
+StandardError=tty
+EOF
+        cp testsuite.sh $initdir/
+
+        setup_testsuite
+    ) || return 1
+
+    ddebug "umount $TESTDIR/root"
+    umount $TESTDIR/root
+}
+
+do_test "$@"

test/TEST-19-DELEGATE/testsuite.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+# -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
+# ex: ts=8 sw=4 sts=4 et filetype=sh
+set -ex
+set -o pipefail
+
+systemd-run --wait --unit=test0.service -p "DynamicUser=1" -p "Delegate=" \
+            test -w /sys/fs/cgroup/system.slice/test0.service/ -a \
+                 -w /sys/fs/cgroup/system.slice/test0.service/cgroup.procs -a \
+                 -w /sys/fs/cgroup/system.slice/test0.service/cgroup.subtree_control
+
+systemd-run --wait --unit=test1.service -p "DynamicUser=1" -p "Delegate=memory pids" \
+            grep memory /sys/fs/cgroup/system.slice/test1.service/cgroup.controllers
+
+systemd-run --wait --unit=test2.service -p "DynamicUser=1" -p "Delegate=memory pids" \
+            grep pids /sys/fs/cgroup/system.slice/test2.service/cgroup.controllers
+
+echo OK > /testok
+
+exit 0