Add unit tests for utils

**Problem**
When working with validation, 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 utils validation code and the existing unit-test setup. Review how validation failures currently report errors, then add tests covering the relevant cases and confirm the messages are more descriptive; run the project's test command to verify the suite passes.

Written by the indexing model from the issue text.