Tests: validation against metaschema

[rhiaro]

The additional properties added to the metaschema are codelist, openCodelist, version and propertyOrder. Only version can be validated because it sits at the top level - for any nested properties, the validator ignores our metaschema and defers back to the 2020-12 metaschema.

To fix this, I think we need to also redefine $ref in our metaschema, or possibly use the workaround for the jsonschema library in python-jsonschema/jsonschema#994 (comment).

See also: python-jsonschema/jsonschema#1061

Maybe an alternative fix would be to turn the BODS metaschema into a vocabulary but I can't see that the python-jsonschema library supports this yet.

[kd-ods]

@rhiaro - is this an issue for the future? It seems like something where a 'wait and see' policy could be enough for now.

[jpmckinney]

FYI, OCDS creates custom metaschema here (for Draft 4, but hopefully similar for newer JSON Schema versions): https://github.com/open-contracting/standard-maintenance-scripts/blob/bec9acc09c1e5f1ca84b420ab8bbcf8a5cbed79d/tests/test_json.py#L247