Add unit tests for routes

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

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

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

The issue names unit tests for routes and discusses parser error messages, but gives no file, test path, or entry point. Start by locating the route parser and existing unit-test setup; done means tests cover the relevant parser errors and verify more descriptive messages.

Written by the indexing model from the issue text.