name: Backend Unit Tests

on:
  push:
    branches: [master, main]
  pull_request:
    branches: [master, main]

jobs:
  test:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Set up Python 3.11
        uses: actions/setup-python@v5
        with:
          python-version: '3.11'

      # Cache pip dependencies to speed up repeated runs
      - name: Cache pip
        uses: actions/cache@v4
        with:
          path: ~/.cache/pip
          key: pip-${{ hashFiles('backend/requirements.txt') }}

      - name: Install backend dependencies
        run: pip install -r backend/requirements.txt

      - name: Install test dependencies
        run: pip install pytest pytest-asyncio

      # Run only UNIT tests (test/backend/unit/).
      # These tests have zero external dependencies — no QEMU binary, no arduino-cli,
      # no running backend server.
      #
      # NOT included here (must be run manually on Windows with QEMU DLLs):
      #   test/backend/integration/  — needs arduino-cli + QEMU binary
      #   test/backend/e2e/          — JS tests, need running backend + QEMU + arduino-cli
      #   Run e2e tests locally: scripts\run-e2e-tests.bat
      - name: Run backend unit tests
        # CI=true is set automatically by GitHub Actions.
        # Tests decorated with @unittest.skipIf(CI=='true', ...) are skipped here
        # (e.g. timing-sensitive tests that use busy-wait).
        run: pytest test/backend/unit/ -v --tb=short