tests/functional: move uncompress handling into new uncompress.py file

More uncompress related code will be added shortly, so having a
separate file makes more sense.

The utils.py imports the functions from archive.py, so that
existing callers don't need to be modified. This avoids
redundant code churn until later in the series when all
calls will be adapted for other reasons.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20241217155953.3950506-18-berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/functional/qemu_test/uncompress.py

@@ -0,0 +1,36 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# Utilities for python-based QEMU tests
+#
+# Copyright 2024 Red Hat, Inc.
+#
+# Authors:
+#  Thomas Huth <thuth@redhat.com>
+
+import gzip
+import lzma
+import os
+import shutil
+
+
+def gzip_uncompress(gz_path, output_path):
+    if os.path.exists(output_path):
+        return
+    with gzip.open(gz_path, 'rb') as gz_in:
+        try:
+            with open(output_path, 'wb') as raw_out:
+                shutil.copyfileobj(gz_in, raw_out)
+        except:
+            os.remove(output_path)
+            raise
+
+def lzma_uncompress(xz_path, output_path):
+    if os.path.exists(output_path):
+        return
+    with lzma.open(xz_path, 'rb') as lzma_in:
+        try:
+            with open(output_path, 'wb') as raw_out:
+                shutil.copyfileobj(lzma_in, raw_out)
+        except:
+            os.remove(output_path)
+            raise