test-network: add testcase for no managed interface

(cherry picked from commit 56dfde0)

Author: yuwata

test/test-network/systemd-networkd-tests.py

@@ -867,7 +867,7 @@ def wait_online(self, links_with_operstate, timeout='20s', bool_any=False, ipv4=
         This returns if the links reached the requested operstate/setup_state; otherwise it
         raises CalledProcessError or fails test assertion.
         """
-        args = wait_online_cmd + [f'--timeout={timeout}'] + [f'--interface={link}' for link in links_with_operstate]
+        args = wait_online_cmd + [f'--timeout={timeout}'] + [f'--interface={link}' for link in links_with_operstate] + [f'--ignore={link}' for link in protected_links]
         if bool_any:
             args += ['--any']
         if ipv4:
@@ -1103,6 +1103,10 @@ def setUp(self):
     def tearDown(self):
         tear_down_common()
 
+    def test_wait_online_all_unmanaged(self):
+        start_networkd()
+        self.wait_online([])
+
     def test_wait_online_any(self):
         copy_network_unit('25-bridge.netdev', '25-bridge.network', '11-dummy.netdev', '11-dummy.network')
         start_networkd()