[tests] allow service bind9 stop to fail (openthread#11438)

Author: jwhui

tests/scripts/thread-cert/border_router/internet/test_multi_border_routers.py

@@ -100,7 +100,7 @@ def test(self):
         # ensure NAT64 is enabled here.
         br1.nat64_set_enabled(True)
         self.simulator.go(config.LEADER_STARTUP_DELAY)
-        br1.bash("service bind9 stop")
+        br1.bash("service bind9 stop || true")
         self.simulator.go(NAT64_PREFIX_REFRESH_DELAY)
         self.assertEqual('leader', br1.get_state())
 
@@ -167,7 +167,7 @@ def test(self):
         # Case 3. Re-enables BR2 with a local prefix and it will not add
         #         its local nat64 prefix to Network Data.
         #
-        br2.bash("service bind9 stop")
+        br2.bash("service bind9 stop || true")
         self.simulator.go(5)
         br2.nat64_set_enabled(True)
 

tests/scripts/thread-cert/border_router/internet/test_single_border_router.py

@@ -123,7 +123,7 @@ def test(self):
         # ensure NAT64 is enabled here.
         br.nat64_set_enabled(True)
         self.simulator.go(config.LEADER_STARTUP_DELAY)
-        br.bash("service bind9 stop")
+        br.bash("service bind9 stop || true")
         self.simulator.go(330)
         self.assertEqual('leader', br.get_state())
 

tests/scripts/thread-cert/border_router/internet/test_upstream_dns.py

@@ -91,7 +91,7 @@ def test(self):
         self._start_dns_server(dns_server_2, TEST_DOMAIN_2, TEST_DOMAIN_IP6_ADDRESSES_2)
 
         # Disable the bind9 service on the BR otherwise bind9 may respond to Thread devices' DNS queries
-        br.bash('service bind9 stop')
+        br.bash('service bind9 stop || true')
 
         br.start()
         self.simulator.go(config.LEADER_STARTUP_DELAY)
@@ -144,7 +144,7 @@ def _start_dns_server(self, dns_server, test_domain, test_domain_ip6_addresses):
 ''' + '\n'.join(f'@ IN AAAA {addr}' for addr in test_domain_ip6_addresses)
 
         dns_server.start(start_radvd=False)
-        dns_server.bash('service bind9 stop')
+        dns_server.bash('service bind9 stop || true')
 
         dns_server.bash(shlex.join(['echo', test_domain_bind_conf]) + ' >> /etc/bind/named.conf.local')
         dns_server.bash(shlex.join(['echo', test_domain_bind_zone]) + ' >> /etc/bind/db.test.domain')

tests/scripts/thread-cert/border_router/internet/test_with_infrastructure_prefix.py

@@ -157,7 +157,7 @@ def test(self):
         self.simulator.go(5)
 
         # Case 5 Infrastructure nat64 prefix no longer presents
-        br.bash("service bind9 stop")
+        br.bash("service bind9 stop || true")
         self.simulator.go(NAT64_PREFIX_REFRESH_DELAY)
 
         local_nat64_prefix = br.get_br_nat64_prefix()