Add GitHub Action to run style checks on notebooks (#6)

Use `nbqa` to run `ruff` and `black` to check style format of notebooks.
Add a `Makefile` with targets for checking and formatting the notebooks.
Add a `.github/requirements-style.yml` file with dependencies to run the
checks.

.github/requirements-style.txt

@@ -0,0 +1,3 @@
+nbqa==1.7.1
+ruff==0.1.13
+black==23.12.1

.github/workflows/style.yml

@@ -0,0 +1,65 @@
+# Linting and style checks with GitHub Actions
+#
+# NOTE: Pin actions to a specific commit to avoid having the authentication
+# token stolen if the Action is compromised. See the comments and links here:
+# https://github.com/pypa/gh-action-pypi-publish/issues/27
+#
+# Use nbQA to run linters and code formatters on notebooks
+#
+name: code-style
+
+# Only build PRs and the main branch. Pushes to branches will only be built
+# when a PR is opened.
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+
+###############################################################################
+jobs:
+  ruff:
+    name: ruff
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          persist-credentials: false
+
+      - name: Setup Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: "3.11"
+
+      - name: Install requirements
+        run: pip install -r .github/requirements-style.txt
+
+      - name: List installed packages
+        run: pip freeze
+
+      - name: Check code format
+        run: make ruff
+
+  black:
+    name: black
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          persist-credentials: false
+
+      - name: Setup Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: "3.11"
+
+      - name: Install requirements
+        run: pip install -r .github/requirements-style.txt
+
+      - name: List installed packages
+        run: pip freeze
+
+      - name: Check code format
+        run: make black

Makefile

@@ -0,0 +1,22 @@
+NOTEBOOKS_DIR=notebooks
+
+.PHONY: help black ruff check format
+
+help:
+	@echo "Commands:"
+	@echo ""
+	@echo "  check     run code style and quality checks (black and ruff)"
+	@echo "  format    run black and ruff to format notebooks"
+	@echo ""
+
+check: ruff black
+
+ruff:
+	nbqa ruff ${NOTEBOOKS_DIR}/*.ipynb
+
+black:
+	nbqa black --check ${NOTEBOOKS_DIR}/*.ipynb
+
+format:
+	nbqa black ${NOTEBOOKS_DIR}/*.ipynb
+	nbqa ruff --fix ${NOTEBOOKS_DIR}/*.ipynb

environment.yml

@@ -13,3 +13,7 @@ dependencies:
   - ipython
   - jupyter
   - jupyterlab
+  # Linters
+  - nbqa==1.7.1
+  - ruff==0.1.13
+  - black==23.12.1