Merge pull request #1132 from XueqiangWei/readonly_floppy

qemu.test: readyonly_floppy, get virt_data_dir dynamically

qemu/tests/cfg/readonly_floppy.cfg

 - readonly_floppy:
     virt_test_type = qemu
     type = readonly_floppy
+    start_vm = no
     no pseries
     no q35
     floppies = "fl1 fl2"
     floppy_name_fl1 = "images/fd1.img"
     floppy_name_fl2 = "images/fd2.img"
-    pre_command = "dd if=/dev/urandom of=/usr/share/avocado/data/avocado-vt/images/fd1.img bs=512 count=2880 && cp -af /usr/share/avocado/data/avocado-vt/images/fd{1.img,2.img}"
+    pre_cmd = "dd if=/dev/urandom of=%s/images/fd1.img bs=512 count=2880 && cp -af %s/images/fd{1.img,2.img}"
     format_floppy_timeout = 60
     floppy_readonly = yes
     # This command maybe different in differnet guests. It may covered by guest-os.cfg

qemu/tests/readonly_floppy.py

 import logging
 import time
 import re
+from virttest import data_dir
+from virttest import env_process
 from autotest.client.shared import error
 
 
@@ -24,6 +26,11 @@ def run(test, params, env):
     :param env: Dictionary with test environment.
     """
 
+    vt_data_dir = data_dir.get_data_dir()
+    if params.get("start_vm") == "no":
+        params["start_vm"] = "yes"
+        params["pre_command"] = params.get("pre_cmd") % (vt_data_dir, vt_data_dir)
+        env_process.preprocess(test, params, env)
     error.context("Boot up guest with floppies", logging.info)
     vm = env.get_vm(params["main_vm"])
     vm.verify_alive()