ITC-012_Modbus_ConfigWrite_Invalid_Handling
===========================================

Verify invalid IF_ConfigUpdate payloads are rejected cleanly across Modbus-to-config interoperability boundary.

Execution
---------

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   * - Field
     - Value
   * - Status
     - pass
   * - Test Type
     - interface_contract
   * - Last Run At
     - 2026-02-28T18:11:57Z
   * - Last Runner
     - Dummy_Integration_Run

Preconditions
-------------

Invalid payload injection is available and baseline configuration snapshot is recorded before execution.

Procedure
---------

Send malformed and out of range IF_ConfigUpdate payloads and verify rejection with unchanged active configuration.

Expected Result
---------------

Invalid contract payloads are rejected without unintended mutation and interoperability path remains stable for subsequent valid updates.

Traceability
------------

.. list-table::
   :header-rows: 1

   * - Element Type
     - Referenced Elements
   * - SW Unit Relations
     -
       * :doc:`SWR-020 </generated/detailed_design/relations/swr-020-fbf5d76d-87e9-4bf5-8203-94fe5044896a>`
   * - SW Interfaces
     -
       * :doc:`IF_ConfigUpdate </generated/interfaces/if-configupdate-f20fedaa-4e6c-420f-8340-89cf13274267>`
   * - SW Sequences
     -
       * SEQ-004_Modbus_Event_Servicing
   * - SW Timing Budgets
     - n/a