Pagination unit tests

[AetherUnbound]

Current Situation

A bug that was recently fixed in WordPress/openverse-api#398 involved the pagination.py utilities, which currently don't appear to have tests.

Suggested Improvement

It would be great to add unit tests for this file!

Benefit

Additional context

Implementation

• 🙋 I would be interested in implementing this feature.

[prikshit-1103]

hi @dhruvkb @AetherUnbound can i work on this issue, i am comfortable in python and Django and i think I will be able to handle this, can you please assign this to me.

[dhruvkb]

Thanks @prikshit-1103, feel free to take this up! Assigning to you.

[sarayourfriend]

Rather than unit tests, I'd suggest adding pagination to the integration test suite. It's more important to test the pagination utilities as they are used by the paginated views, and testing it in isolation could easily miss some of the finer points (like the fact that page_count and results count are technically initialised late in the request cycle by the view, just before the response is made, rather than by the actual pagination utility.

Writing this, it occurs to me that we're not using the pagination at all the way its intended. It's meant to automatically handle pagination of query sets, but we don't use a query set in these routes. We might be better off writing an extention to serializers.ListSerializer that encodes pagination metadata into the response (and nests the results into the results key), rather than hacking around the DRF pagination utilities.