Add unit tests for handlers

**Description**
Currently middleware lacks proper logging support.

**Proposed solution**
Add configurable logging with sensible defaults.

**Priority**: Low/Medium

Start by locating the middleware and handler entry points, then inspect any existing unit-test structure and logging code. Define done as configurable middleware logging with sensible defaults, covered by unit tests for the handler behavior; the issue does not name specific files or test paths.

Written by the indexing model from the issue text.