Installer test: add static DNS configuration test

Driver installer supports restoring DNS configurations after driver
upgrade, so add a DNS checkpoint here.

Reference: The previous static IP configuration test was #3860
Signed-off-by: wji <wji@redhat.com>

qemu/tests/win_virtio_driver_update_by_installer.py

@@ -96,6 +96,14 @@ def change_virtio_media(cdrom_virtio):
             static_ip_address = utils_net.get_guest_ip_addr(session_serial, virtio_nic_mac, os_type='windows')
             if static_ip_address != params["static_ip"]:
                 test.fail("Failed to setup static ip,current ip is %s" % static_ip_address)
+            setup_dns_cmd = params["setup_dns_cmd"] % ifname
+            session_serial.cmd_status(setup_dns_cmd)
+            static_dns_address = utils_net.get_windows_nic_attribute(session_serial, global_switch="nicconfig",
+                                                                     key="MACAddress", value=f"{virtio_nic_mac}",
+                                                                     target="DNSServerSearchOrder")
+            static_dns_address = static_dns_address.strip('{}').strip('"')
+            if static_dns_address != params["static_dns"]:
+                test.fail("Failed to setup static dns,current dns is %s" % static_dns_address)
         session_serial.close()
     else:
         for driver_name, device_name, device_hwid in zip(
@@ -128,6 +136,12 @@ def change_virtio_media(cdrom_virtio):
         static_ip_address = utils_net.get_guest_ip_addr(session_serial, virtio_nic_mac, os_type='windows')
         if static_ip_address != params["static_ip"]:
             test.fail("Static ip is lost after upgrade driver,current ip is %s" % static_ip_address)
+        static_dns_address = utils_net.get_windows_nic_attribute(session_serial, global_switch="nicconfig",
+                                                                 key="MACAddress", value=f"{virtio_nic_mac}",
+                                                                 target="DNSServerSearchOrder")
+        static_dns_address = static_dns_address.strip('{}').strip('"')
+        if static_dns_address != params["static_dns"]:
+            test.fail("Static dns is lost after upgrade driver,current dns is %s" % static_dns_address)
         session_serial.close()
 
     # for some guests, need to reboot guest after drivers are updated