gh-273: add tests for `glass.shells` #448

	---
	name: Test examples

	on:
	push:
	paths:
	- glass/**
	branches:
	- main
	pull_request:
	paths:
	- glass/**
	types:
	- opened
	- ready_for_review
	- reopened
	- synchronize

	concurrency:
	cancel-in-progress: true
	group: >-
	${{ github.workflow }}-${{ github.event.pull_request.number \|\| github.ref }}

	jobs:
	test-examples:
	if: github.event.pull_request.draft == false
	name: Test examples
	runs-on: ubuntu-latest
	steps:
	- name: Checkout source
	uses: actions/checkout@v4
	with:
	fetch-depth: 0

	- name: Cache nox
	uses: actions/cache@v4
	with:
	key: test-${{ hashFiles('pyproject.toml') }}
	path: .nox

	- name: Set up Python
	uses: actions/setup-python@v5
	with:
	cache-dependency-path: pyproject.toml
	cache: pip
	python-version: 3.x

	- name: Install nox
	run: python -m pip install nox

	- name: Run examples
	run: nox -s examples
	env:
	FORCE_COLOR: 1

	- name: Generate HTML
	run: nox -s examples -- html
	env:
	FORCE_COLOR: 1

	- name: Upload artefact
	uses: actions/upload-artifact@v4
	with:
	name: Examples
	path: examples/*/.html

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