Add unit tests for helpers

**Problem**
When working with handlers, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

Start by locating the handlers, helper implementations, and any existing unit-test conventions in the repository. The issue is complete when handler errors are more descriptive and unit tests cover the affected helpers, but the specific cases and files still need to be identified.

Written by the indexing model from the issue text.