test: pytestify "tests/unittests/config/test_cc_timezone.py" (canonic…

…al#5885)

Refactors the code in the file "tests/unittests/config/test_cc_timezone.py" 
using pytest. This helps remove dependance of this test on 
"tests/unittests/helpers.py:FileSystemMockingTestCase"

Fixes: part of canonicalGH-5760

tests/unittests/config/test_cc_timezone.py

@@ -5,46 +5,35 @@
 # This file is part of cloud-init. See LICENSE file for license information.
 
 import logging
-import shutil
-import tempfile
 from io import BytesIO
 
 from configobj import ConfigObj
 
 from cloudinit import util
 from cloudinit.config import cc_timezone
-from tests.unittests import helpers as t_help
 from tests.unittests.util import get_cloud
 
 LOG = logging.getLogger(__name__)
 
 
-class TestTimezone(t_help.FilesystemMockingTestCase):
-    def setUp(self):
-        super(TestTimezone, self).setUp()
-        self.new_root = tempfile.mkdtemp()
-        self.addCleanup(shutil.rmtree, self.new_root)
-        self.patchUtils(self.new_root)
-        self.patchOS(self.new_root)
-
-    def test_set_timezone_sles(self):
+class TestTimezone:
 
+    def test_set_timezone_sles(self, fake_filesystem):
         cfg = {
             "timezone": "Tatooine/Bestine",
         }
         cc = get_cloud("sles")
-
         # Create a dummy timezone file
         dummy_contents = "0123456789abcdefgh"
         util.write_file(
             "/usr/share/zoneinfo/%s" % cfg["timezone"], dummy_contents
         )
-
         cc_timezone.handle("cc_timezone", cfg, cc, [])
 
         contents = util.load_binary_file("/etc/sysconfig/clock")
         n_cfg = ConfigObj(BytesIO(contents))
-        self.assertEqual({"TIMEZONE": cfg["timezone"]}, dict(n_cfg))
+
+        assert {"TIMEZONE": cfg["timezone"]} == dict(n_cfg)
 
         contents = util.load_text_file("/etc/localtime")
-        self.assertEqual(dummy_contents, contents.strip())
+        assert dummy_contents == contents.strip()