guest_os_booting: Add a case of update-device

This PR adds:
    VIRT-297949 - [Negative] Update device with boot order

Signed-off-by: Yingshun Cui <[email protected]>

libvirt/tests/cfg/guest_os_booting/negative/update_device_boot_order.cfg

@@ -0,0 +1,5 @@
+- guest_os_booting.update_device.boot_order:
+    type = update_device_boot_order
+    start_vm = no
+    boot_index = 1
+    err_msg = "cannot modify field .*boot order.*"

libvirt/tests/src/guest_os_booting/negative/update_device_boot_order.py

@@ -0,0 +1,42 @@
+from virttest.libvirt_xml import vm_xml
+from virttest import virsh
+from virttest.utils_test import libvirt
+
+from provider.guest_os_booting import guest_os_booting_base
+
+
+def run(test, params, env):
+    """
+    Update disk device with boot order
+    """
+    vm_name = guest_os_booting_base.get_vm(params)
+    boot_index = params.get("boot_index")
+    err_msg = params.get('err_msg')
+
+    vm = env.get_vm(vm_name)
+    vmxml = vm_xml.VMXML.new_from_inactive_dumpxml(vm.name)
+    bkxml = vmxml.copy()
+
+    try:
+        test.log.info("TEST_STEP: Prepare a running guest with boot order "
+                      "element in disk xml.")
+        vm_os = vmxml.os
+        vm_os.del_boots()
+        vmxml.os = vm_os
+        disk_obj = vmxml.devices.by_device_tag('disk')[0]
+        disk_attrs = disk_obj.fetch_attrs()
+        vmxml.set_boot_order_by_target_dev(
+            disk_attrs['target']['dev'], params.get('boot_index'))
+        vmxml.xmltreefile.write()
+        test.log.debug(f"vmxml after updating: {vmxml}")
+        vmxml.sync()
+        vm.start()
+        vm.wait_for_login()
+
+        test.log.info("TEST_STEP: Update device.")
+        disk_obj.boot = int(boot_index) + 1
+        res = virsh.update_device(vm.name, disk_obj.xml, debug=True)
+        libvirt.check_result(res, err_msg)
+    finally:
+        test.log.info("TEST_TEARDOWN: Recover test environment.")
+        bkxml.sync()