[PATCH v2 19/31] tests/functional: add common deb_extract helper

[Daniel P . Berrangé]

This mirrors the existing archive_extract, cpio_extract and zip_extract
helpers

Signed-off-by: Daniel P. Berrangé <berra...@redhat.com>
---
 tests/functional/qemu_test/archive.py     | 13 +++++++++++++
 tests/functional/qemu_test/linuxkernel.py | 13 ++++---------
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/tests/functional/qemu_test/archive.py 
b/tests/functional/qemu_test/archive.py
index 06b66701c0..a6fc97a557 100644
--- a/tests/functional/qemu_test/archive.py
+++ b/tests/functional/qemu_test/archive.py
@@ -12,6 +12,8 @@
 import tarfile
 import zipfile
 
+from .cmd import run_cmd
+
 
 def tar_extract(archive, dest_dir, member=None):
     with tarfile.open(archive) as tf:
@@ -37,3 +39,14 @@ def zip_extract(archive, dest_dir, member=None):
             zf.extract(member=member, path=dest_dir)
         else:
             zf.extractall(path=dest_dir)
+
+def deb_extract(archive, dest_dir, member=None):
+    cwd = os.getcwd()
+    os.chdir(dest_dir)
+    try:
+        (stdout, stderr, ret) = run_cmd(['ar', 't', archive])
+        file_path = stdout.split()[2]
+        run_cmd(['ar', 'x', archive, file_path])
+        tar_extract(file_path, dest_dir, member)
+    finally:
+        os.chdir(cwd)
diff --git a/tests/functional/qemu_test/linuxkernel.py 
b/tests/functional/qemu_test/linuxkernel.py
index 2e4f4e35fd..8f2810f3af 100644
--- a/tests/functional/qemu_test/linuxkernel.py
+++ b/tests/functional/qemu_test/linuxkernel.py
@@ -6,8 +6,9 @@
 import os
 
 from .testcase import QemuSystemTest
-from .cmd import run_cmd, wait_for_console_pattern
-from .utils import archive_extract
+from .cmd import wait_for_console_pattern
+from .archive import deb_extract
+
 
 class LinuxKernelTest(QemuSystemTest):
     KERNEL_COMMON_COMMAND_LINE = 'printk.time=0 '
@@ -37,13 +38,7 @@ def extract_from_deb(self, deb_path, path):
         :param path: path within the deb archive of the file to be extracted
         :returns: path of the extracted file
         """
-        cwd = os.getcwd()
-        os.chdir(self.workdir)
-        (stdout, stderr, ret) = run_cmd(['ar', 't', deb_path])
-        file_path = stdout.split()[2]
-        run_cmd(['ar', 'x', deb_path, file_path])
-        archive_extract(file_path, self.workdir)
-        os.chdir(cwd)
+        deb_extract(deb_path, self.workdir, member="." + path)
         # Return complete path to extracted file.  Because callers to
         # extract_from_deb() specify 'path' with a leading slash, it is
         # necessary to use os.path.relpath() as otherwise scratch_file()
-- 
2.46.0