---
id: TST-COM-CAT-131
title: Stacking Verification
kind: unit
product_area: commerce
module: catalog
revision: 1
status: draft
product_intent: proposed
source_sha:
  services-commerce: c8b66a98e2490617aec38ba5c8165dd9bd0a8f9b
repository: services-commerce
files:
  - modules/promotions/tests/unit/pricing/stacking.spec.js
implements:
  - ATS-COM-CAT-016-03
  - ATS-COM-CAT-016-04
environment: mock
implementation_state: implemented
latest_result: not-run
latest_run_at: null
latest_run_ref: null
conformance: not-verified
estimated_minutes: 1
isolation: In-process fixtures; any shared port replacement is restored by the suite.
binding_evidence:
  - scenario: ATS-COM-CAT-016-03
    source: >-
      services-commerce:modules/promotions/tests/unit/pricing/stacking.spec.js#puts automatic
      promotions first by priority, then the codes in the order entered
  - scenario: ATS-COM-CAT-016-03
    source: >-
      services-commerce:modules/promotions/tests/unit/pricing/stacking.spec.js#J16: an automatic 10%
      stackable then a 15% stackable code on 20000 give 2000 then 2700, net 15300
  - scenario: ATS-COM-CAT-016-04
    source: >-
      services-commerce:modules/promotions/tests/unit/pricing/stacking.spec.js#refuses any promotion
      on a line an exclusive one holds
evidence:
  - 'services-commerce:modules/promotions/tests/unit/pricing/stacking.spec.js'
  - >-
    services-commerce:modules/promotions/tests/unit/pricing/stacking.spec.js#Real: the stacking, the
    orchestration, the validation, the arithmetic.
  - >-
    services-commerce:modules/promotions/tests/unit/pricing/stacking.spec.js#Doubled: nothing.
    proves_controls: [TC-PI-002]
execution_constraints:
  - No execution is performed in this documentation back-fill.
verification_boundary: >-
  Bindings identify the existing assertions contributing to each scenario; several suites can
  jointly cover a compound scenario.
---

# Stacking Verification

## Verification Boundary

The suite exercises the isolated rule, calculation or adapter with its supplied fixtures. It does not establish storage or distributed behaviour.

## What This Suite Proves

The stacking assertions contribute to the scenarios listed in the register. Each binding retains its exact source test anchor so a reviewer can distinguish an individual contribution from the complete scenario.

## What It Does Not Prove

The register records source inspection only. It establishes no run result, delivery qualification or Product approval.

## Real Dependencies and Test Doubles

The production function under test is real. Its collaborators are supplied as fixtures or replaced ports where the suite declares them.

## Must Not Be Doubled

Keep the production function under test and its refusal or arithmetic result real. Replacing that function with a fixture removes the claimed proof.