Add unit tests for validation

**Feature request**
It would be great to have filtering for components.

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

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

Start by locating the configuration validation code and existing unit-test conventions for config options. Reconcile the title's request for validation tests with the body’s filtering feature and `enable_filtering` default of `false`; done should include agreed filtering behavior and passing tests.

Written by the indexing model from the issue text.