test: drop FilesystemMockingTestCase in netconfig

Author: aciba90

tests/unittests/conftest.py

@@ -39,6 +39,7 @@ def m_gpg():
         ("relpath", 1),
     ],
     os: [
+        ("chown", 2),
         ("listdir", 1),
         ("mkdir", 1),
         ("rmdir", 1),
@@ -76,8 +77,18 @@ def m_gpg():
 
 
 @pytest.fixture
-def fake_filesystem(mocker, tmpdir):
-    """Mocks fs functions to operate under `tmpdir`"""
+def fake_filesystem_hook():
+    """A hook to interact with the real filesystem before mocking it in
+    fake_filesystem"""
+
+
+@pytest.fixture
+def fake_filesystem(mocker, tmpdir, fake_filesystem_hook):
+    """Mocks fs functions to operate under `tmpdir`
+
+    fix_cloud_init_project_dir requested to sort it before this fixture to
+    bypass fs faking.
+    """
     # This allows fake_filesystem to be used with production code that
     # creates temporary directories. Functions like TemporaryDirectory()
     # attempt to create a directory under "/tmp" assuming that it already