{"foo_bar": 1}: schema accepts, model accepts
{"foo_bar": 1, "foo-bar": "s", "x": "t"}: schema accepts, model accepts
{"foo-bar": "s"}: schema rejects, model rejects
{"foo_bar": 1, "foo-bar": 2}: schema rejects, model rejects
{"foo_bar": 1, "x": null}: schema rejects, model rejects
