---
id: PLN-0161
ticket: system-os-cartridge-switch-orchestrator
title: Validate Stress To Dummy Boy Game Switch End To End
status: done
created: 2026-07-05
ref_decisions: [DEC-0039]
tags: [runtime, os, lifecycle, game, cartridge, architecture]
---

## Briefing

DEC-0039 requires proof that `Game A -> Home -> Game B` creates a fresh Game
session and does not present stale state from Game A. The minimum evidence is
switching from Stress to Dummy Boy.

## Objective

Add end-to-end validation for `Stress -> Home -> Dummy Boy` through the real
Hub/Home flow, proving lifecycle, VM session, cartridge identity, and render
ownership switch correctly.

## Dependencies

- Source decision: DEC-0039.
- Requires PLN-0157 target contract.
- Requires PLN-0158 destructive replacement.
- Requires PLN-0159 failed-switch recovery for negative path assertions.
- Requires PLN-0160 Dummy Boy cartridge.

## Scope

- Add firmware/system tests that drive:
  - launch Stress from games root;
  - request Home;
  - launch Dummy Boy;
  - assert Stress session is gone;
  - assert Dummy Boy session is active;
  - assert cartridge identity and render ownership belong to Dummy Boy.
- Add a negative end-to-end test for broken Game B returning to Home if not
  already covered by PLN-0159.
- Use existing test platform/render submission inspection where possible.

## Non-Goals

- Do not require final launcher UX.
- Do not add screenshot-based host automation unless existing test utilities
  make it cheap and deterministic.
- Do not implement additional Game-to-Game variants beyond Stress to Dummy Boy.

## Execution Method

1. Inspect existing firmware tests in
   `crates/console/prometeu-firmware/src/firmware/firmware.rs`.
2. Reuse existing `TestGameRoot` or games-root helpers to expose Stress and
   Dummy Boy.
3. Drive input through Hub/Home selection rather than calling cartridge load
   directly when possible.
4. Assert lifecycle/session invariants:
   - old task closed/stopped;
   - old VM session removed;
   - new VM session created;
   - foreground owner is new Game;
   - current cartridge identity is Dummy Boy.
5. Assert render invariants:
   - render ownership epoch belongs to Dummy Boy app identity;
   - stale Stress submissions are not accepted after switch;
   - latest observable Game frame comes from Dummy Boy when render inspection is
     available.
6. Add a focused test for failure path if missing after PLN-0159.

## Acceptance Criteria

- End-to-end test proves Stress can be replaced by Dummy Boy from Home.
- Stress is not resumable after switching to Dummy Boy.
- Dummy Boy receives a fresh VM session.
- Cartridge identity and active render ownership are Dummy Boy after switch.
- Failure path returns Home and does not restore Stress.
- Tests are deterministic and do not rely on manual host interaction.

## Tests

- `cargo test -p prometeu-firmware`
- `cargo test -p prometeu-system`
- `cargo test -p prometeu-host-desktop-winit`
- `cargo clippy -p prometeu-system -p prometeu-firmware -p prometeu-host-desktop-winit --all-targets -- -D warnings`

## Affected Artifacts

- `crates/console/prometeu-firmware/src/firmware/firmware.rs`
- `crates/console/prometeu-system/src/services/game_library.rs`
- `test-cartridges/dummy-boy`
- Host/render test utilities if needed