Add unit tests for models

**Feature request**
It would be great to have search for handlers.

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

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

The issue names no files, tests, or entry points. Start by locating the handler implementation and configuration parsing, then determine how handler search should work and where unit tests for models belong. Done means the `enable_search` option defaults to `false`, the requested search behavior is covered by tests, and the issue's stated model tests are addressed.

Written by the indexing model from the issue text.