diff --git a/test/units/testsuite-05.effective-limit.sh b/test/units/testsuite-05.effective-limit.sh
new file mode 100755
index 0000000000..3ff8e83140
--- /dev/null
+++ b/test/units/testsuite-05.effective-limit.sh
@@ -0,0 +1,68 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: LGPL-2.1-or-later
+set -eux
+set -o pipefail
+
+# shellcheck source=test/units/util.sh
+. "$(dirname "$0")"/util.sh
+
+pre=test05
+cat >/run/systemd/system/"$pre"alpha.slice <<EOF
+[Slice]
+MemoryMax=40M
+MemoryHigh=40M
+TasksMax=400
+EOF
+
+cat >/run/systemd/system/"$pre"alpha-beta.slice <<EOF
+[Slice]
+MemoryMax=10M
+MemoryHigh=10M
+TasksMax=100
+EOF
+
+cat >/run/systemd/system/"$pre"alpha-beta-gamma.slice <<EOF
+[Slice]
+MemoryMax=20M
+MemoryHigh=20M
+TasksMax=200
+EOF
+
+systemctl daemon-reload
+
+srv=probe.service
+slc0="$pre"alpha.slice
+slc="$pre"alpha-beta-gamma.slice
+
+systemd-run --unit "$srv" --slice "$slc"  \
+    -p MemoryMax=5M \
+    -p MemoryHigh=5M \
+    -p TasksMax=50 \
+    sleep inf
+
+# Compare with inequality because test can run in a constrained container
+assert_le "$(systemctl show -P EffectiveMemoryMax "$srv")" "5242880"
+assert_le "$(systemctl show -P EffectiveMemoryHigh "$srv")" "5242880"
+assert_le "$(systemctl show -P EffectiveTasksMax "$srv")" "50"
+
+systemctl stop "$srv"
+
+systemd-run --unit "$srv" --slice "$slc"  \
+    sleep inf
+
+assert_le "$(systemctl show -P EffectiveMemoryMax "$srv")" "10485760"
+assert_le "$(systemctl show -P EffectiveMemoryHigh "$srv")" "10485760"
+assert_le "$(systemctl show -P EffectiveTasksMax "$srv")" "100"
+
+systemctl set-property "$slc0" \
+    MemoryMax=5M \
+    MemoryHigh=5M \
+    TasksMax=50
+
+assert_le "$(systemctl show -P EffectiveMemoryMax "$srv")" "5242880"
+assert_le "$(systemctl show -P EffectiveMemoryHigh "$srv")" "5242880"
+assert_le "$(systemctl show -P EffectiveTasksMax "$srv")" "50"
+
+systemctl stop "$srv"
+
+rm -f /run/systemd/system/"$pre"* || :
diff --git a/test/units/util.sh b/test/units/util.sh
index a18c8980cf..66f9c73ba6 100755
--- a/test/units/util.sh
+++ b/test/units/util.sh
@@ -28,6 +28,15 @@ assert_eq() {(
     fi
 )}
 
+assert_le() {(
+    set +ex
+
+    if [[ "${1:?}" -gt "${2:?}" ]]; then
+        echo "FAIL: '$1' > '$2'" >&2
+        exit 1
+    fi
+)}
+
 assert_in() {(
     set +ex