Standardized Locale Testing Framework/Design

## Feature Request

It would be nice if we could create/develop some kind of framework, or testing design to standardize the testing of locales. It would help clean up the locale testing file, as well as give us a much more comprehensive and thorough way to ensure to test locales (see #1022).

Start by reviewing the locale testing file and issue #1022, which are the only implementation references provided. Determine the proposed testing framework or design, the locales and behaviors it must cover, and how comprehensive coverage would be verified; the issue is complete when a decided, documented approach is implemented and the locale tests are standardized.

Written by the indexing model from the issue text.