[displaymanager] SPDX tags for tests

src/modules/displaymanager/tests/CMakeTests.txt

@@ -1,3 +1,6 @@
+#   SPDX-FileCopyrightText: no
+#   SPDX-License-Identifier: CC0-1.0
+#
 # We have tests to load (some) of the DMs specifically, to test their
 # configuration code. Those tests conventionally live in Python
 # files here in the tests/ directory. Add them.

src/modules/displaymanager/tests/test-dm-greetd.py

@@ -1,3 +1,6 @@
+#   SPDX-FileCopyrightText: no
+#   SPDX-License-Identifier: CC0-1.0
+#
 # Calamares Boilerplate
 import libcalamares
 libcalamares.globalstorage = libcalamares.GlobalStorage(None)

src/modules/displaymanager/tests/test-dm-sddm.py

@@ -1,3 +1,6 @@
+#   SPDX-FileCopyrightText: no
+#   SPDX-License-Identifier: CC0-1.0
+#
 # Calamares Boilerplate
 import libcalamares
 libcalamares.globalstorage = libcalamares.GlobalStorage(None)