[Testing] Need to Add Specific Tests for Tagging Scenarios

[BethanyG]

Currently, tags are being tested as a side effect of Resources. Given the issues we've already uncovered, we need to create specific tests for tagging and tag formatting that are pulled out into their own tag test files. We also need test data for these tests.

Not an exhaustive list, but here are some use cases we need to test for:

1. Non-English extended ASCII characters as part of tags (see bug [API] Non-English (unicode, extended ASCII, emoji) Characters Cannot Be Slug-ified in Tags #71 )
2. Unicode characters as part of tags
3. "Special" characters (slashes, semicolons, anything that might read as code) as part of tags
4. Nested JSON in tags
5. Nested lists in tags
6. Malformed or otherwise weirdly formatted tags
7. Duplicate tags (to test de-duping)
8. Various capitalization scenarios
9. Adding tags to an existing set
10. Removing tags from an existing set

[BethanyG]

Yes - the tags on the issue are weird. But it is both a bug we don't have tests, and and enhancement that we add all the scenarios.

[lpatmo]

👏 Great list. There's validation the front-end form can do of course, but would be good to validate if we're making API requests directly too. I have no idea how to implement testing against duplicate tags in DRF so this would be good learning for me...

[BethanyG]

Pulling this into a branch where I am working on multiple proposed changed to tags.