Add unit tests for store

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

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

**Priority**: Low/Medium

Start by locating the middleware store and any existing unit-test coverage; the issue does not name files or an entry point. Clarify whether the expected change is configurable sorting, new tests for existing behavior, or both, then define sensible defaults and verify them with unit tests.

Written by the indexing model from the issue text.