GHA: Optimize Ubuntu job

* Use global `env` for Linux and MacOS
* Use astral-sh/setup-uv for caching
* Set UV_FROZEN and UV_NO_SYNC to prevent updating Python
  packages
* Use "uv run" consistently
* Install test group instead of devel group

Author: tomschr

.github/workflows/ci.yml

@@ -23,6 +23,13 @@ permissions:
   packages: read
   pull-requests: write
 
+# GLOBAL ENV: Applies to ALL jobs (Linux & macOS)
+env:
+  # Strict lockfile checks for everyone, equivalent to passing --frozen to every command
+  UV_FROZEN: "1"
+  # Needed for coverage/multiprocessing reliability
+  PYTHONSTARTMETHOD: spawn
+
 jobs:
   test-ubuntu:
     name: ubuntu-python-${{ matrix.python-version }}
@@ -39,6 +46,7 @@ jobs:
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
+
       - name: Get dependencies
         run: |
           rpm -q daps \
@@ -67,37 +75,29 @@ jobs:
 
       - name: Install uv
         id: setup-uv
-        run: |
-          python3 -m venv .venv
-          source .venv/bin/activate
-          pip install uv
-
-      - name: Print the installed version
-        run: echo "Installed uv version is $(.venv/bin/uv --version)"
+        uses: astral-sh/setup-uv@v7
+        with:
+          enable-cache: true
+          cache-dependency-glob: "uv.lock"
 
       - name: Install dependencies and Coverage Tools
-        run: |
-          source .venv/bin/activate
-          uv sync --frozen --group devel
-          # CRITICAL FIX: Ensure coverage tools are installed for the CI runner
-          pip install coverage pytest-cov
+        run: uv sync --group tests
 
       - name: Run tests and Report Coverage
+        env:
+          UV_NO_SYNC: "1"  # Disable uv sync during test runs
         run: |
-          source .venv/bin/activate
-          # 1. Run tests and collect coverage for src/ and tests/
-          pytest --cov=src --cov=tests --cov-report=term-missing -vv
+          # Using 'uv run' avoids the need to manually source .venv/bin/activate
+          uv run pytest --cov=src --cov=tests --cov-report=term-missing -vv
 
-          # 2. Combine data
-          python -m coverage combine --append || true
+          # Combine data
+          uv run python -m coverage combine --append || true
 
-          # 3. Generate report and save to file (using tee to see it in logs too)
-          python -m coverage report | tee coverage.txt
+          # Generate report
+          uv run python -m coverage report | tee coverage.txt
 
-          # 4. Cleanup coverage data
-          python -m coverage erase # Final cleanup
-        env:
-          PYTHONSTARTMETHOD: spawn
+          # Cleanup
+          uv run python -m coverage erase
 
       - name: Create Coverage Comment for ${{ github.event.pull_request.head.sha || github.sha }}
         if: success() && github.event_name == 'pull_request' && matrix.python-version == '3.12'
@@ -183,6 +183,8 @@ jobs:
 
       # Install uv and project dependencies inside a virtual environment
       - name: Install uv and dependencies
+        env:
+          UV_NO_SYNC: "1"  # Disable uv sync during test runs
         run: |
           python3 -m venv .venv
           source .venv/bin/activate