Add unit tests for hooks

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

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

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

No files or tests are named. Start by locating the hook and helper implementations, their existing configuration handling, and the current unit-test entry point. Done means caching is controlled by an `enable_caching` option that defaults to `false`, with unit tests covering the new behavior.

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