diff --git a/test/units/testsuite-15.sh b/test/units/testsuite-15.sh
index f847adac744..5f7387fb8b2 100755
--- a/test/units/testsuite-15.sh
+++ b/test/units/testsuite-15.sh
@@ -3,30 +3,32 @@
 set -eux
 set -o pipefail
 
-_clear_service () {
-    local SERVICE_NAME="${1:?}"
-    systemctl stop "$SERVICE_NAME.service" 2>/dev/null || :
-    rm -f  /{etc,run,usr/lib}/systemd/system/"$SERVICE_NAME".service
-    rm -fr /{etc,run,usr/lib}/systemd/system/"$SERVICE_NAME".service.d
-    rm -fr /{etc,run,usr/lib}/systemd/system/"$SERVICE_NAME".service.{wants,requires}
-    if [[ $SERVICE_NAME == *@ ]]; then
-        systemctl stop "$SERVICE_NAME"*.service 2>/dev/null || :
-        rm -f  /{etc,run,usr/lib}/systemd/system/"$SERVICE_NAME"*.service
-        rm -fr /{etc,run,usr/lib}/systemd/system/"$SERVICE_NAME"*.service.d
-        rm -fr /{etc,run,usr/lib}/systemd/system/"$SERVICE_NAME"*.service.{wants,requires}
+clear_unit () {
+    local UNIT_NAME="${1:?}"
+    systemctl stop "$UNIT_NAME" 2>/dev/null || :
+    rm -f  /{etc,run,usr/lib}/systemd/system/"$UNIT_NAME"
+    rm -fr /{etc,run,usr/lib}/systemd/system/"$UNIT_NAME".d
+    rm -fr /{etc,run,usr/lib}/systemd/system/"$UNIT_NAME".{wants,requires}
+    if [[ $UNIT_NAME == *@ ]]; then
+        local base="${UNIT_NAME%@*}"
+        local suffix="${UNIT_NAME##*.}"
+        systemctl stop "$base@"*."$suffix" 2>/dev/null || :
+        rm -f  /{etc,run,usr/lib}/systemd/system/"$base@"*."$suffix"
+        rm -fr /{etc,run,usr/lib}/systemd/system/"$base@"*."$suffix".d
+        rm -fr /{etc,run,usr/lib}/systemd/system/"$base@"*."$suffix".{wants,requires}
     fi
 }
 
-clear_services () {
+clear_units () {
     for u in "$@"; do
-        _clear_service "$u"
+        clear_unit "$u"
     done
     systemctl daemon-reload
 }
 
 create_service () {
     local SERVICE_NAME="${1:?}"
-    clear_services "$SERVICE_NAME"
+    clear_units "${SERVICE_NAME}".service
 
     cat >/etc/systemd/system/"$SERVICE_NAME".service <<EOF
 [Unit]
@@ -119,7 +121,7 @@ EOF
     check_ok test15-b ExecCondition "/bin/echo test15-b"
     rm -rf /usr/lib/systemd/system/service.d
 
-    clear_services test15-a test15-b test15-c test15-c1
+    clear_units test15-{a,b,c,c1}.service
 }
 
 test_linked_units () {
@@ -146,7 +148,7 @@ test_linked_units () {
                                           # Make sure it is completely ignored.
 
     rm /test15-a@.scope
-    clear_services test15-a test15-b
+    clear_units test15-{a,b}.service
 }
 
 test_template_alias() {
@@ -172,7 +174,7 @@ test_template_alias() {
     check_ko test15-b@other Names test15-a@other.service
     check_ok test15-b@other Names test15-b@other.service
 
-    clear_services test15-a@ test15-b@
+    clear_units test15-{a,b}@.service
 }
 
 test_hierarchical_dropins () {
@@ -197,7 +199,7 @@ ExecCondition=/bin/echo $dropin
         rm -rf /usr/lib/systemd/system/$dropin
     done
 
-    clear_services a-b-c
+    clear_units a-b-c.service
 }
 
 test_template_dropins () {
@@ -346,7 +348,7 @@ EOF
     check_ok bar-alias@3 Requires yup-template-requires.device
     check_ok bar-alias@3 Requires yup-3-requires.device
 
-    clear_services foo {bar,yup,bar-alias}@{,1,2,3}
+    clear_units foo.service {bar,yup,bar-alias}@{,1,2,3}.service
 }
 
 test_alias_dropins () {
@@ -361,7 +363,7 @@ test_alias_dropins () {
     systemctl --quiet is-active test15-b
     systemctl stop test15-a test15-b
     rm /etc/systemd/system/test15-b1.service
-    clear_services test15-a test15-b
+    clear_units test15-{a,b}.service
 
     # Check that dependencies don't vary.
     echo "*** test 2"
@@ -378,7 +380,7 @@ test_alias_dropins () {
     systemctl stop test15-a test15-x test15-y
     rm /etc/systemd/system/test15-a1.service
 
-    clear_services test15-a test15-x test15-y
+    clear_units test15-{a,x,y}.service
 }
 
 test_masked_dropins () {
@@ -499,7 +501,7 @@ EOF
     ln -sf /dev/null /etc/systemd/system/test15-a.service.requires/test15-b.service
     check_ok test15-a Requires test15-b
 
-    clear_services test15-a test15-b
+    clear_units test15-{a,b}.service
 }
 
 test_invalid_dropins () {
@@ -511,7 +513,7 @@ test_invalid_dropins () {
     # Assertion failed on earlier versions, command exits unsuccessfully on later versions
     systemctl cat a@.service || true
     systemctl stop a
-    clear_services a
+    clear_units a.service
     return 0
 }
 
@@ -531,7 +533,7 @@ EOF
     ln -s /tmp/testsuite-15-test15-a-dropin-directory-regular /usr/lib/systemd/system/test15-a.service.d
     check_ok test15-a Description hogehoge
 
-    clear_services test15-a
+    clear_units test15-a.service
 }
 
 test_basic_dropins