Fix mock_DeviceModel defaulting manufacturer to None

[HugoFara]

Motivation

mock_DeviceModel has been unusable since it was introduced in #2088.

It declares manufacturer: str = None, but DeviceModel.__init__ requires manufacturer to be a str (it is a required docval argument with no default). Every call therefore raises:

TypeError: DeviceModel.__init__: None is not allowed for 'manufacturer' (expected 'str', not None)

This went unnoticed because mock_DeviceModel is referenced by no test — it was never added to the mock_functions list in tests/unit/test_mock.py that drives the parametrized test_mock and test_mock_write tests. pynwb.testing.mock is a public, documented surface used by downstream packages, so the mock being non-functional is a real defect rather than an internal test-only concern.

This PR defaults manufacturer to "manufacturer", matching the existing description: str = "description" convention in the same module, and adds mock_DeviceModel to the parametrized list so the behavior is covered going forward.

The annotation manufacturer: str also becomes truthful, where previously it was annotated str but defaulted to None.

How to test the behavior?

Before this change, on dev:

>>> from pynwb.testing.mock.device import mock_DeviceModel
>>> mock_DeviceModel()
TypeError: DeviceModel.__init__: None is not allowed for 'manufacturer' (expected 'str', not None)

After this change the call succeeds, and the object round-trips and validates:

from pynwb import NWBHDF5IO, validate
from pynwb.testing.mock.file import mock_NWBFile
from pynwb.testing.mock.device import mock_DeviceModel

nwbfile = mock_NWBFile()
dm = mock_DeviceModel(nwbfile=nwbfile)
with NWBHDF5IO("dm.nwb", "w") as io:
    io.write(nwbfile)
assert not validate(path="dm.nwb")

The two new parametrizations fail on dev and pass with this change. Confirmed by applying only the test change and reverting the source fix:

FAILED tests/unit/test_mock.py::test_mock[mock_DeviceModel] - TypeError: DeviceModel.__init__: None is not allowed for 'manufacturer'
FAILED tests/unit/test_mock.py::test_mock_write[mock_DeviceModel] - TypeError: DeviceModel.__init__: None is not allowed for 'manufacturer'

Results with the full change applied, run locally on Python 3.14, HDMF 6.x:

Command	Result
pytest tests/unit	563 passed, 3 skipped (561 before; the 2 new are the added parametrizations)
pytest tests/integration/hdf5	212 passed, 3 skipped
ruff check .	All checks passed
codespell	clean

Schema validation ran through the pynwb.validate API, both in the snippet above and inside the integration round-trip suite, which validates every file it writes. The python -m pynwb.validate CLI was not invoked separately.

Checklist

• Did you update CHANGELOG.md with your changes?
• Have you checked our Contributing document?
• Have you ensured the PR clearly describes the problem and the solution?
• Is your contribution compliant with our coding style? This can be checked running ruff check . && codespell from the source directory.
• Have you checked to ensure that there aren't other open Pull Requests for the same change?
• Have you included the relevant issue number using "Fix #XXX" notation where XXX is the issue number? By including "Fix #XXX" you allow GitHub to close issue #XXX when the PR is merged.

No existing issue covers this; I searched the issue tracker and open PRs for mock_DeviceModel and found none. Happy to open one first if you would prefer that order.

---

Disclosure: this contribution was prepared with assistance from Claude Opus 5. The defect was found by programmatically constructing every pynwb.testing.mock object and writing/validating the result. All commands reported above were executed locally and their output is reproduced as returned.