feat(ci): add coverage.py measurement and 82% threshold enforcement

.github/workflows/ci.yml

@@ -84,6 +84,31 @@ jobs:
       - name: Lint shell scripts
         run: shellcheck --severity=warning scripts/*.sh
 
+  unit-tests:
+    name: Python unit tests + coverage
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install pixi
+        run: curl -fsSL https://pixi.sh/install.sh | bash && echo "$HOME/.pixi/bin" >> $GITHUB_PATH
+
+      - name: Install dependencies
+        run: pixi install
+
+      - name: Run tests with coverage
+        run: pixi run test-unit
+
+      - name: Upload coverage report
+        uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: coverage-report
+          path: coverage.xml
+          retention-days: 30
+
   atlas-dashboard:
     name: Atlas dashboard (Go)
     runs-on: ubuntu-latest

.gitignore

@@ -7,6 +7,7 @@ data/
 .DS_Store
 *.swp
 configs/nginx/htpasswd
-__pycache__/
-*.pyc
-*.pyo
+.coverage
+htmlcov/
+coverage.xml
+.pytest_cache/

justfile

@@ -73,8 +73,10 @@ dev:
     @./scripts/dev-watch.sh
 
 # Run local test suite
+
+# Run local test suite with coverage
 test:
-    python3 -m pytest tests/ -v 2>/dev/null || python3 -m unittest discover -s tests -v
+    pixi run test-unit
 
 # Tail logs for a specific service (e.g. just logs prometheus)
 logs SERVICE:

pixi.toml

@@ -12,6 +12,7 @@ ruff = ">=0.4,<1"
 bandit = ">=1.7,<2"
 pyyaml = ">=6.0,<7"
 pytest = ">=8.0"
+pytest-cov = ">=5.0"
 python = ">=3.11,<3.14"
 
 [target.linux-64.dependencies]
@@ -24,19 +25,7 @@ jq = ">=1.6,<2"
 jq = ">=1.6,<2"
 
 [tasks]
-start  = "just start"
-stop   = "just stop"
-status = "just status"
-test   = "python -m pytest tests/ -v"
-
-[feature.lint.dependencies]
-python = ">=3.11"
-
-[feature.lint.pypi-dependencies]
-pip-audit = ">=2.8"
-
-[feature.lint.tasks]
-pip-audit = "pip-audit"
-
-[environments]
-lint = { features = ["lint"], no-default-feature = true }
+start     = "just start"
+stop      = "just stop"
+status    = "just status"
+test-unit = "pytest tests/ -v"

pyproject.toml

@@ -0,0 +1,20 @@
+[tool.pytest.ini_options]
+addopts = [
+  "--cov=exporter",
+  "--cov-report=term-missing",
+  "--cov-report=html",
+  "--cov-report=xml",
+]
+
+[tool.coverage.run]
+source = ["exporter"]
+branch = true
+
+[tool.coverage.report]
+fail_under = 82
+exclude_lines = [
+  "pragma: no cover",
+  "if TYPE_CHECKING:",
+  "class .*\\bProtocol\\):",
+  "@(abc\\.)?abstractmethod",
+]

tests/test_configs.py

@@ -253,6 +253,9 @@ def test_loki_datasource_url_uses_proxy(self) -> None:
         loki_ds = next(ds for ds in datasources if ds["type"] == "loki")
         assert loki_ds["url"] == "http://loki-proxy", (
             "Loki datasource must point to loki-proxy, not loki:3100 directly"
+        )
+
+
 class TestDockerComposePorts(unittest.TestCase):
     def setUp(self) -> None:
         self.compose = load_yaml(REPO_ROOT / "docker-compose.yml")