Add feature meta-tests to cover standard.json

[andylolz]

There are currently meta-tests for rules (which can be thought of as unit tests.)

standard.json could also be covered by meta-tests (which could be thought of as feature tests.)

[samuele-mattiuzzo]

Even better, would be nice if our meta-test xml examples reflected the structure of standard.json (the good/bad split is decent enough and can be kept) so that the official Ruleset document is constantly kept tested (and we won't require double intervention if an existing rule changes slightly in logic, by updating both standard.json and rule_name_test_example.json)

[andylolz]

You’re right – that would be better!

But additionally, would be cool to ensure standard.json is valid somehow. I had a go at this just here, but I don’t know if that’s of interest.