Unit test failures in TestNetplanValidateNetworkSchema

[palash-gandhi]

Bug report

We are seeing test failures, specifically in test_network_config_schema_validation_false_when_skipped. It seems like the test code expects that removing the netplan module from sys.modules will cause an ImportError while importing netplan. Here's a stack trace and some debug output from a debugging session:

$ git log -1
commit 0f77b3c13a2f44c224c5dea18d27bbfa4898e39a (HEAD -> main, origin/main, origin/HEAD)
Author: James Falcon <[email protected]>
Date:   Tue Oct 8 14:59:51 2024 -0500

    chore: Use devel release and no sbuild in integration CI (#5798)

$ python3 -m pytest -v tests/unittests cloudinit -k 'test_network_config_schema_validation_false_when_skipped' --pdb
===================================================== test session starts =====================================================
platform linux -- Python 3.12.3, pytest-7.4.4, pluggy-1.4.0 -- /usr/bin/python3
cachedir: .pytest_cache
rootdir: /home/ubuntu/cloud-init-pstream
configfile: tox.ini
plugins: mock-3.12.0
collected 5142 items / 5138 deselected / 4 selected

tests/unittests/config/test_schema.py::TestNetplanValidateNetworkSchema::test_network_config_schema_validation_false_when_skipped[config0-] FAILED [ 25%]
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> captured log >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
2024-10-08 23:23:26 DEBUG     cloudinit.util:util.py:2290 Writing to /tmp/tmpr2kaczoy/etc/netplan/network-config.yaml - wb: [600] 20 bytes
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> traceback >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

self = <tests.unittests.config.test_schema.TestNetplanValidateNetworkSchema object at 0x7ea520414140>, config = {}
expected_log = '', caplog = <_pytest.logging.LogCaptureFixture object at 0x7ea51f363ef0>

    @pytest.mark.parametrize(
        "config,expected_log",
        (
            ({}, ""),
            ({"version": 1}, ""),
            (
                {"version": 2},
                "Skipping netplan schema validation. No netplan API available",
            ),
            (
                {"network": {"version": 2}},
                "Skipping netplan schema validation. No netplan API available",
            ),
        ),
    )
    def test_network_config_schema_validation_false_when_skipped(
        self, config, expected_log, caplog
    ):
        """netplan_validate_network_schema returns false when skipped."""
        with mock.patch.dict("sys.modules"):
            sys.modules.pop("netplan", None)
>           assert False is netplan_validate_network_schema(config)
E           assert False is True
E            +  where True = netplan_validate_network_schema({})

tests/unittests/config/test_schema.py:438: AssertionError
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> entering PDB >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> PDB post_mortem (IO-capturing turned off) >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> /home/ubuntu/cloud-init-pstream/tests/unittests/config/test_schema.py(438)test_network_config_schema_validation_false_when_skipped()
-> assert False is netplan_validate_network_schema(config)
(Pdb) "netplan" in sys.modules
False
(Pdb) from netplan import NetplanParserException
(Pdb) "netplan" in sys.modules
True
(Pdb) sys.modules.pop("netplan", None)
<module 'netplan' from '/usr/lib/python3/dist-packages/netplan/__init__.py'>
(Pdb) from netplan import NetplanParserException
(Pdb)

Steps to reproduce the problem

On Ubuntu 24.04, run make unittest or to run only the failing tests, run this command:

python3 -m pytest -v tests/unittests cloudinit -k 'test_network_config_schema_validation_false_when_skipped' --pdb

Environment details

• Cloud-init version: Commit 0f77b3c13a2f44c224c5dea18d27bbfa4898e39a of branch main
• Operating System Distribution: Ubuntu 24.04 LTS
• Cloud provider, platform or installer type: AWS

cloud-init logs

Not applicable since these are unit test failures.

[TheRealFalcon]

@palash-gandhi , thanks! I put up a fix at #5805