testing: Add Missing Test Cases for Untested or Newly Added Features

Description

As the framework has evolved, new features, refactors, and behavioral changes have been introduced without corresponding test coverage. This issue focuses on identifying gaps in test coverage and adding meaningful test cases to improve reliability and confidence.

This is not about rewriting existing tests, but about covering what is currently untested.

Tasks

• Identify core components, packages, or flows with little or no test coverage
• Prioritize critical paths (HTTP lifecycle, kernel, validation, CLI, etc.)
• Add unit and/or integration tests for missing cases
• Ensure tests follow existing testing conventions and structure
• Avoid testing implementation details; focus on observable behavior

Acceptance Criteria

• New tests cover previously untested or under-tested functionality
• Tests are meaningful, deterministic, and maintainable
• No significant framework feature remains completely untested
• Test coverage improves without introducing flaky tests

Difficulty

• Medium (can be split into smaller sub-tasks)