[Awesome-Ace22]

What and why

This pull request introduces significant improvements to the build system, testing, and simulation support for the project. It adds a new hardware-free build mode for CI and development, improves documentation for simulated hardware, and enhances testability and script portability. The most important changes are grouped below.

Build system and simulation improvements:

• Added a new Meson build option hardware to allow building only hardware-independent code and tests, enabling CI and laptop builds without requiring Pi-specific libraries. The build now produces a novaMock executable that runs the full application on simulated hardware, with scenario files controlling simulated sensors and faults. (meson_options.txt, meson.build, docs/simulation.md, docs/setup.md) [1] [2] [3] [4] [5] [6]

• Refactored the build system to split core, simulated, and real hardware code, and to only link hardware-dependent libraries when needed. The novaMock executable and its smoke test are now only built and run if dependencies are available. (meson.build) [1] [2] [3]

Continuous Integration and testing:

• Enhanced CI workflow to add shell linting (shellcheck), contract testing for scripts, BATS tests for scripts, and a new core-tests job that builds and tests hardware-free code on multiple architectures and with sanitizers. (.github/workflows/pr-checks.yml)

• Improved script testability by allowing all paths in nova-pi.sh and run.sh to be redirected to a scratch root via the NOVA_PI_ROOT environment variable. This enables safe testing without touching the real Pi. (nova-pi.sh, run.sh) [1] [2] [3] [4]

Codebase cleanup and modernization:

• Updated the GPIO controller to use the new DigitalIo interface instead of the old GPIO_Manager, improving abstraction and compatibility with simulated hardware. (src/controllers/gpio_controller.cpp, src/controllers/gpio_controller.hpp) [1] [2] [3]

• Improved the main control loops to support cooperative cancellation via std::stop_token, and replaced busy-waiting with interruptible sleeps, making the code more robust and responsive to shutdown requests. (src/controllers/loops.cpp) [1] [2] [3]

Other improvements:

• Ensured all shell and BATS scripts use LF line endings for compatibility. (.gitattributes)

Closes UTATRocketry/Nova-Collected#4

How was this tested?

• 1 Unit / Automated Test - CI
• 2 Simulator Test - testing procedure with the hardware simulators
• 3 Bench Test - testing procedure on the dev stack, with some real hardware
• 4 Integration Test - full engine test procedure, real hardware, no propellants

Hardware impact

• None - UI, docs or tooling only
• Changes how a sensor is read, converted or shown
• Changes how an actuator is commanded, or safety rules, interlocks, timeouts or sequencing → add the hardware-risk label; a lead must approve
• Changes a message format, MQTT topic or FAS protocol that another repo depends on → title needs !, link the matching PRs:

Checklist

• Targets dev (or main for a release/hotfix, or with a reason given above)
• Branch is up to date ("Update branch" button)
• No station config/calibrations, data files, secrets, .env files or build output committed
• README/docs updated if behaviour changed