test-network: retry networkctl status in wait_operstate()

networkctl status may transiently fail right after start_networkd() because networkd has not yet picked up the freshly-created link from the kernel. The retry loop in wait_operstate() did not catch the resulting subprocess.CalledProcessError, so the test aborted on the first attempt instead of retrying for the configured timeout.

Observed in TEST-85-NETWORK-NetworkdBridgeTests, subtest test_bridge_configure_without_carrier[no-slave]:

  [   19.600156] systemd-networkd-tests.py[526]: Failed to issue io.systemd.Network.Link.Describe() varlink call: Invalid argument
  [   53.124982] systemd[1]: systemd-networkd.service: Changed start -> running
  [   53.336167] systemd-networkd-tests.py[526]: ERROR: test_bridge_configure_without_carrier (__main__.NetworkdBridgeTests.test_bridge_configure_without_carrier) (test='no-slave')
  [   53.336167] systemd-networkd-tests.py[526]:     self.wait_operstate('bridge99', operstate=r'(no-carrier|routable)', setup_state=None, setup_timeout=30)
  [   53.336167] systemd-networkd-tests.py[526]: subprocess.CalledProcessError: Command '['/usr/bin/networkctl', '-n', '0', 'status', 'bridge99']' returned non-zero exit status 1.

Co-developed-by: Claude Opus 4.7 <noreply@anthropic.com>
(cherry picked from commit 446b0393ff)
(cherry picked from commit eacfec289e)

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

@@ -1226,7 +1226,13 @@ class Utilities():
             if not link_exists(link):
                 time.sleep(0.5)
                 continue
-            output = networkctl_status(link)
+            try:
+                output = networkctl_status(link)
+            except subprocess.CalledProcessError:
+                # networkctl status may transiently fail e.g. when networkd has not
+                # yet picked up the link from the kernel. Retry until the timeout.
+                time.sleep(0.5)
+                continue
             if re.search(rf'(?m)^\s*State:\s+{operstate}\s+\({setup_state}\)\s*$', output):
                 return True
             time.sleep(0.5)