various: mark files with the usual license tags

For .clang-format and pytest.ini, MIT-0 is used because people might want
to copy those.

test/integration-tests/TEST-03-JOBS/TEST-03-JOBS.units/always-activating.service

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Unit]
 Description=Service that never leaves state ACTIVATING
 Requires=always-activating.socket

test/integration-tests/TEST-03-JOBS/TEST-03-JOBS.units/always-activating.socket

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Unit]
 Description=Socket that activates always-activating.service
 

test/integration-tests/TEST-04-JOURNAL/TEST-04-JOURNAL.units/delegated-cgroup-filtering.service

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Unit]
 Description=Test service for delegated logs filtering
 

test/integration-tests/TEST-04-JOURNAL/TEST-04-JOURNAL.units/logs-filtering-syslog.service

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Unit]
 Description=Log filtering unit
 

test/integration-tests/TEST-04-JOURNAL/TEST-04-JOURNAL.units/logs-filtering.service

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Unit]
 Description=Log filtering unit
 

test/integration-tests/TEST-07-PID1/TEST-07-PID1.units/defer-reactivation.service

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Unit]
 Description=Test for DeferReactivation=yes (service)
 

test/integration-tests/TEST-07-PID1/TEST-07-PID1.units/defer-reactivation.timer

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Unit]
 Description=Test for DeferReactivation=yes (timer)
 

test/integration-tests/TEST-07-PID1/TEST-07-PID1.units/issue2730.mount

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Mount]
 What=tmpfs
 Where=/issue2730

test/integration-tests/TEST-23-UNIT-FILE/TEST-23-UNIT-FILE.units/TEST-23-UNIT-FILE-openfile-server.socket

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Unit]
 Description=OpenFile= test server socket
 

test/integration-tests/TEST-23-UNIT-FILE/TEST-23-UNIT-FILE.units/TEST-23-UNIT-FILE-openfile-server@.service

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Unit]
 Description=OpenFile= test server service
 

test/integration-tests/TEST-23-UNIT-FILE/TEST-23-UNIT-FILE.units/success-failure-test-failure.service

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Service]
 Type=notify
 ExecStart=bash -c "echo failure >>/tmp/success-failure-test-result && systemd-notify --ready && sleep infinity"

test/integration-tests/TEST-23-UNIT-FILE/TEST-23-UNIT-FILE.units/success-failure-test-success.service

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Service]
 Type=notify
-ExecStart=bash -c "echo success >> /tmp/success-failure-test-result && systemd-notify --ready && sleep infinity"
+ExecStart=bash -c "echo success >>/tmp/success-failure-test-result && systemd-notify --ready && sleep infinity"

test/integration-tests/TEST-23-UNIT-FILE/TEST-23-UNIT-FILE.units/success-failure-test.service

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Unit]
 OnSuccess=success-failure-test-success.service
 OnFailure=success-failure-test-failure.service

test/test-dlopen-note.py

@@ -1,4 +1,6 @@
 #!/usr/bin/env python3
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 """
 Compare statically linked dlopen symbols against shared library ELF notes.
 

test/test-execute/exec-personality-loongarch64.service

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Unit]
 Description=Test for Personality=loongarch64
 

test/test-network/conf/25-bond-property.netdev

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [NetDev]
 Name=bond97
 Kind=bond

test/test-network/conf/26-bridge-vlan-tunnel.network

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
 [Match]
 Name=dummy97
 

test/test-sysusers/test-00-basic.input

@@ -1,9 +1,4 @@
-#  This file is part of systemd.
-#
-#  systemd is free software; you can redistribute it and/or modify it
-#  under the terms of the GNU Lesser General Public License as published by
-#  the Free Software Foundation; either version 2.1 of the License, or
-#  (at your option) any later version.
+# SPDX-License-Identifier: LGPL-2.1-or-later
 
 # The superuser
 g root    0       -            -

test/units/TEST-19-CGROUP.ExitType-cgroup.sh

@@ -1,4 +1,5 @@
 #!/usr/bin/env bash
+# SPDX-License-Identifier: LGPL-2.1-or-later
 set -eux
 
 # Test ExitType=cgroup