support/testing/tests: new NetworkManager/GOI test

This test is inspired from the details provided by Fiona Klute's cover
letter for a GOI/glib bump series at:

  https://lore.kernel.org/buildroot/20250120211707.2381182-1-fiona.klute@gmx.de/

Which itself uses the example code at:

  https://networkmanager.dev/docs/developers/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

DEVELOPERS

@@ -1103,6 +1103,8 @@ F:	package/python-dunamai/
 F:	package/python-poetry-dynamic-versioning/
 F:	package/python-pyasynchat/
 F:	package/python-pyasyncore/
+F:	support/testing/tests/package/sample_python_networkmanager_goi.py
+F:	support/testing/tests/package/test_python_networkmanager_goi.py
 
 N:	Flávio Tapajós <flavio.tapajos@newtesc.com.br>
 F:	configs/asus_tinker-s_rk3288_defconfig

support/testing/tests/package/sample_python_networkmanager_goi.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+
+# This script is from https://networkmanager.dev/docs/developers/
+
+import gi
+gi.require_version("NM", "1.0")
+from gi.repository import NM  # noqa: E402
+
+
+def print_values(setting, key, value, flags, data):
+    print("     {}.{}: {}".format(setting.get_name(), key, value))
+
+
+# Create the client object. This automatically loads all the D-Bus
+# tree and creates in-memory objects for connections, devices, access
+# points, etc.
+client = NM.Client.new(None)
+
+# Obtain a list of connection profiles ...
+connections = client.get_connections()
+
+# ... and print their properties
+for c in connections:
+    print("{}:".format(c.get_id()))
+    c.for_each_setting_value(print_values, None)
+    print("\n")

support/testing/tests/package/test_python_networkmanager_goi.py

@@ -0,0 +1,24 @@
+from tests.package.test_python import TestPythonPackageBase
+
+
+class TestPythonPy3NetworkmanagerGoi(TestPythonPackageBase):
+    __test__ = True
+    # Can't use TestPythonPackageBase.config because we need headers
+    # >= 4.20 for network-manager, so we have to use the bleeding-edge
+    # toolchain.
+    config = \
+        """
+        BR2_arm=y
+        BR2_TOOLCHAIN_EXTERNAL=y
+        BR2_TOOLCHAIN_EXTERNAL_BOOTLIN=y
+        BR2_TOOLCHAIN_EXTERNAL_BOOTLIN_ARMV5_EABI_GLIBC_BLEEDING_EDGE=y
+        BR2_PACKAGE_PYTHON3=y
+        BR2_PACKAGE_PYTHON_GOBJECT=y
+        BR2_INIT_SYSTEMD=y
+        BR2_PACKAGE_NETWORK_MANAGER=y
+        BR2_TARGET_ROOTFS_CPIO=y
+        # BR2_TARGET_ROOTFS_TAR is not set
+        """
+    sample_scripts = ["tests/package/sample_python_networkmanager_goi.py"]
+
+    timeout = 30