1.  Integration of comprehensive functional tests (`TestUserPromoFeed`) that verify core endpoint behaviors:
    - Accurate user-specific promo targeting based on age and country.
    - Correct dynamic calculation of promo 'active' status (considering dates, usage counts, and unique code availability).
    - Effective filtering via `active` (boolean) and `category` (case-insensitive) query parameters.
    - Proper pagination functionality using `limit` and `offset`, including `X-Total-Count` header validation.
    - Verification of response data structure, ensuring exclusion of sensitive promo code values.
    - Correct reflection of promo data updates (e.g., a promo becoming inactive after an edit) in the feed.

2.  Addition of new focused validation tests (`TestUserPromoFeed`) using parameterized inputs to cover edge cases and invalid requests:
    - Authentication checks, specifically ensuring `401 Unauthorized` for requests lacking a token.
    - Rigorous validation of query parameters (`limit`, `offset`, `category`, `active`):
        - Invalid data types and formats (e.g., non-numeric for `limit`/`offset`, non-boolean for `active`).
        - Values outside defined constraints (e.g., negative `limit`/`offset`, category string length violations).
        - Empty string inputs for parameters that require specific formats.
    - Rejection of requests containing unexpected or unsupported query parameters, returning a `400 Bad Request`.