diff --git a/test/test-network/systemd-networkd-tests.py b/test/test-network/systemd-networkd-tests.py
index 000180dd41..c12c28f676 100755
--- a/test/test-network/systemd-networkd-tests.py
+++ b/test/test-network/systemd-networkd-tests.py
@@ -526,7 +526,8 @@ def setup_system_units():
             'ExecStart=',
             f'ExecStart={networkctl_bin} persistent-storage yes',
             'ExecStop=',
-            f'ExecStop={networkctl_bin} persistent-storage no'
+            f'ExecStop={networkctl_bin} persistent-storage no',
+            'Environment=SYSTEMD_LOG_LEVEL=debug' if enable_debug else '',
         ]
     )
 
@@ -579,6 +580,15 @@ def save_existing_links():
     print('### The following links will be protected:')
     print(', '.join(sorted(list(protected_links))))
 
+def unmanage_existing_links():
+    mkdir_p(network_unit_dir)
+
+    with open(os.path.join(network_unit_dir, '00-unmanaged.network'), mode='w', encoding='utf-8') as f:
+        f.write('[Match]\n')
+        for link in protected_links:
+            f.write(f'Name={link}\n')
+        f.write('\n[Link]\nUnmanaged=yes\n')
+
 def flush_links():
     links = os.listdir('/sys/class/net')
     remove_link(*links, protect=True)
@@ -844,6 +854,9 @@ def radvd_check_config(config_file):
 def networkd_invocation_id():
     return check_output('systemctl show --value -p InvocationID systemd-networkd.service')
 
+def networkd_pid():
+    return check_output('systemctl show --value -p MainPID systemd-networkd.service')
+
 def read_networkd_log(invocation_id=None, since=None):
     if not invocation_id:
         invocation_id = networkd_invocation_id()
@@ -875,6 +888,9 @@ def stop_networkd(show_logs=True):
 
 def start_networkd():
     check_output('systemctl start systemd-networkd')
+    invocation_id = networkd_invocation_id()
+    pid = networkd_pid()
+    print(f'Started systemd-networkd.service: PID={pid}, Invocation ID={invocation_id}')
 
 def restart_networkd(show_logs=True):
     global show_journal
@@ -885,6 +901,10 @@ def restart_networkd(show_logs=True):
     if show_logs:
         print(read_networkd_log(invocation_id))
 
+    invocation_id = networkd_invocation_id()
+    pid = networkd_pid()
+    print(f'Restarted systemd-networkd.service: PID={pid}, Invocation ID={invocation_id}')
+
 def networkd_pid():
     return int(check_output('systemctl show --value -p MainPID systemd-networkd.service'))
 
@@ -922,7 +942,14 @@ def udevadm_trigger(*args, action='add'):
     udevadm('trigger', '--settle', f'--action={action}', *args)
 
 def setup_common():
+    # Protect existing links
+    unmanage_existing_links()
+
+    # We usually show something in each test. So, let's break line to make the title of a test and output
+    # from the test mixed. Then, flush stream buffer and journals.
     print()
+    sys.stdout.flush()
+    check_output('journalctl --sync')
 
 def tear_down_common():
     # 1. stop DHCP/RA servers
@@ -955,6 +982,10 @@ def tear_down_common():
     flush_routing_policy_rules()
     flush_routes()
 
+    # 8. flush stream buffer and journals to make not any output from the test with the next one
+    sys.stdout.flush()
+    check_output('journalctl --sync')
+
 def setUpModule():
     rm_rf(networkd_ci_temp_dir)
     cp_r(os.path.join(os.path.dirname(os.path.abspath(__file__)), 'conf'), networkd_ci_temp_dir)
@@ -988,6 +1019,10 @@ def tearDownModule():
     clear_system_units()
     restore_active_units()
 
+    # Flush stream buffer and journals before showing the test summary.
+    sys.stdout.flush()
+    check_output('journalctl --sync')
+
 class Utilities():
     # pylint: disable=no-member
 
@@ -1851,6 +1886,7 @@ class NetworkdNetDevTests(unittest.TestCase, Utilities):
         self.check_tuntap(True)
 
         clear_network_units()
+        unmanage_existing_links()
         restart_networkd()
         self.wait_online('testtun99:off', 'testtap99:off', setup_state='unmanaged')