* Add schema validation helper
* Add tests for cart item schema
* Fix schema errors found by tests
* Add tests and fix validation for remaining store API endpoints
* Tweak response for nested diffs
* Array syntax
* Improved nesting and type validation for schema
* Implement and fix type checking across test suite
* Type validation fixes
* Fix null comparison
* Fix array handling
* Switch to number type and support in validation
* Test the tests
* Update tests to use objects which match schema, avoiding JSON encode/decode
Mike Jolley