qemu.tests: update powerup with target image step

Signed-off-by: NXu Tian <xutian@redhat.com>

qemu/tests/drive_mirror_powerdown.py

 import logging
-from virttest import storage, data_dir
-from autotest.client.shared import error, utils
+from virttest import env_process
+from autotest.client.shared import error
 from qemu.tests import drive_mirror_stress
 
 class DriveMirrorPowerdown(drive_mirror_stress.DriveMirrorStress):
 
     def __init__(self, test, params, env, tag):
         super(DriveMirrorPowerdown, self).__init__(test, params, env, tag)
-        params = self.params.object_params(self.tag)
-        image_file = storage.get_image_filename(params,
-                data_dir.get_data_dir())
-        self.params["image_file"] = image_file
 
     @error.context_aware
     def powerdown(self):
         """
         power down guest via quit qemu;
         """
-        params = self.parser_test_args()
         error.context("powerdown vm", logging.info)
-        self.vm.destroy()
-        error.context("backup base image", logging.info)
-        image_file = params.get("image_file")
-        cmd = "mv %s %s-bak" % (image_file, image_file)
-        utils.system(cmd)
-        return
+        return self.vm.destroy()
 
     @error.context_aware
     def powerup(self):
         """
-        bootup guest with target image, same as reopen new image;
-        steps are:
-        1). backup base image, move target image as base image
-        2). bootup guest with target image;
+        bootup guest with target image;
         """
         params = self.parser_test_args()
-        image_file = params.get("image_file")
-        target_image = params.get("target_image")
-        cmd = "mv -f %s %s" % (target_image, image_file)
-        error.context("copy target image")
-        utils.system(cmd)
+        vm_name = params['main_vm']
+        self.params["image_name"] = params["target_image"]
+        self.params["image_format"] = params["target_format"]
+        logging.info("Target image: %s" % self.target_image)
         error.context("powerup vm with target image", logging.info)
-        self.vm.create()
-
-    def clean(self):
-        params = self.parser_test_args()
-        image_file = params.get("image_file")
-        super(DriveMirrorPowerdown, self).clean()
-        cmd = "mv -f %s-bak %s" % (image_file, image_file)
-        utils.system(cmd)
+        env_process.preprocess_vm(self.test, self.params, self.env, vm_name)
+        vm = self.env.get_vm(vm_name)
+        vm.verify_alive()
+        self.vm = vm
 
 def run_drive_mirror_powerdown(test, params, env):
     """
     drive_mirror_powerdown test:
     1). boot guest, do kernel build
-    3). mirror disk to target image
-    4). wait go into steady status, then quit qemu
+    3). mirror boot disk to target image
+    4). wait mirroring go into ready status then quit qemu
     5). bootup guest with target image
     6). check guest can response correctly