iotests.py: add unarchive_sample_image() helper

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210224104707.88430-6-vsementsov@virtuozzo.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

tests/qemu-iotests/iotests.py

@@ -17,6 +17,7 @@
 #
 
 import atexit
+import bz2
 from collections import OrderedDict
 import faulthandler
 import io
@@ -24,6 +25,7 @@
 import logging
 import os
 import re
+import shutil
 import signal
 import struct
 import subprocess
@@ -96,6 +98,14 @@
                              os.environ.get('IMGKEYSECRET', '')
 luks_default_key_secret_opt = 'key-secret=keysec0'
 
+sample_img_dir = os.environ['SAMPLE_IMG_DIR']
+
+
+def unarchive_sample_image(sample, fname):
+    sample_fname = os.path.join(sample_img_dir, sample + '.bz2')
+    with bz2.open(sample_fname) as f_in, open(fname, 'wb') as f_out:
+        shutil.copyfileobj(f_in, f_out)
+
 
 def qemu_tool_pipe_and_status(tool: str, args: Sequence[str],
                               connect_stderr: bool = True) -> Tuple[str, int]: