[PATCH v2 7/9] tests/avocado/tuxrun_baselines.py: use Avocado's zstd support

[Cleber Rosa <crosa@redhat.com>]

This makes use of the avocado.utils.archive support for zstd.

In order to not duplicate code, the skip condition uses a private
utility from the module which is going to become public in Avocado
versions 103.1 LTS (and also in versions >= 107.0).

Reference: https://github.com/avocado-framework/avocado/pull/5996
Reference: https://github.com/avocado-framework/avocado/pull/5953
Signed-off-by: Cleber Rosa <crosa@redhat.com>
---
 tests/avocado/tuxrun_baselines.py | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/tests/avocado/tuxrun_baselines.py b/tests/avocado/tuxrun_baselines.py
index 736e4aa289..bd02e88ed6 100644
--- a/tests/avocado/tuxrun_baselines.py
+++ b/tests/avocado/tuxrun_baselines.py
@@ -17,6 +17,7 @@
 from avocado_qemu import QemuSystemTest
 from avocado_qemu import exec_command, exec_command_and_wait_for_pattern
 from avocado_qemu import wait_for_console_pattern
+from avocado.utils import archive
 from avocado.utils import process
 from avocado.utils.path import find_command
 
@@ -40,17 +41,12 @@ def get_tag(self, tagname, default=None):
 
         return default
 
+    @skipUnless(archive._probe_zstd_cmd(),
+                'Could not find "zstd", or it is not able to properly '
+                'decompress decompress the rootfs')
     def setUp(self):
         super().setUp()
 
-        # We need zstd for all the tuxrun tests
-        # See https://github.com/avocado-framework/avocado/issues/5609
-        zstd = find_command('zstd', False)
-        if zstd is False:
-            self.cancel('Could not find "zstd", which is required to '
-                        'decompress rootfs')
-        self.zstd = zstd
-
         # Process the TuxRun specific tags, most machines work with
         # reasonable defaults but we sometimes need to tweak the
         # config. To avoid open coding everything we store all these
@@ -99,8 +95,8 @@ def fetch_tuxrun_assets(self, csums=None, dt=None):
                                          asset_hash = isum,
                                          algorithm = "sha256")
 
-        cmd = f"{self.zstd} -d {disk_image_zst} -o {self.workdir}/rootfs.ext4"
-        process.run(cmd)
+        archive.extract(disk_image_zst, os.path.join(self.workdir,
+                                                     "rootfs.ext4"))
 
         if dt:
             dsum = csums.get(dt, None)
-- 
2.45.2