Add unit tests for middleware

**Feature request**
It would be great to have caching for hooks.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_caching` with default `false`.

Start by locating the middleware, hook handling, and configuration entry points; the issue does not name specific files or tests. Clarify whether the task is to add unit tests or implement hook caching, then verify that enable_caching defaults to false and that the requested caching behavior is covered by tests.

Written by the indexing model from the issue text.