This involves writing an integration test to verify the REST API handlers that handle authorization and token exchange for OAuth2 consumers. The corresponding classes are:
- `Authorize` (endpoint: `/oauth2/authorize`)
- `AccessToken` (endpoint: `/oauth2/access_token`)
- `ResetClientSecret` (endpoint: `/oauth2/client/{client_key}/reset_secret`)
We already have a way to write integration tests for REST API handlers in MediaWiki using the `HandlerTestTrait` trait. Some good examples can be found at: https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/core/+/0aa7ce021b7904ed4f63f941f307f0143a32d0bf/tests/phpunit/integration/includes/Rest/Handler
## Impact
[ ] Increase coverage of the REST Handler classes: https://doc.wikimedia.org/cover-extensions/OAuth/src/Rest/Handler/index.html
[ ] Increase in code coverage: https://doc.wikimedia.org/cover-extensions/OAuth/src/Control/ConsumerAcceptanceAccessControl.php.html
[ ] Increase in code coverage: https://doc.wikimedia.org/cover-extensions/OAuth/src/Control/ConsumerAccessControl.php.html