use Tox and OpenAstronomy test workflow

.github/workflows/tests.yml

@@ -0,0 +1,22 @@
+name: tests
+
+on:
+  push:
+    branches:
+      - master
+      - '*x'
+    tags:
+      - '*'
+  pull_request:
+
+jobs:
+  test:
+    uses: OpenAstronomy/github-actions-workflows/.github/workflows/tox.yml@v1
+    with:
+      envs: |
+        - linux: py39-xdist
+        - linux: py310-xdist
+        - linux: py311-xdist
+        - macos: py311-xdist
+        - linux: py311-cov
+          coverage: codecov

pyproject.toml

@@ -1,3 +1,9 @@
 [build-system]
 requires = ["setuptools>=42", "setuptools_scm[toml]>=3.4", "wheel"]
 build-backend = "setuptools.build_meta"
+
+[tool.ruff]
+line-length = 127
+extend-ignore = [
+    "E501", # Line too long
+]

tox.ini

@@ -0,0 +1,47 @@
+[tox]
+env_list =
+    check-{style}
+    test{,-warnings}{,-cov}-xdist
+    build-{docs,dist}
+
+[testenv:check-style]
+description = check code style, e.g. with flake8
+skip_install = true
+deps =
+    ruff
+commands =
+    ruff check . {posargs}
+
+[testenv]
+description =
+    run tests
+    warnings: treating warnings as errors
+    cov: with coverage
+    xdist: using parallel processing
+package = editable
+deps =
+    pytest
+    xdist: pytest-xdist
+    cov: pytest-cov
+commands_pre =
+    pip freeze
+commands =
+    pytest \
+    warnings: -W error \
+    cov: --cov=. --cov-config=pyproject.toml --cov-report=term-missing --cov-report=xml \
+    xdist: -n auto \
+    {posargs}
+
+[testenv:build-docs]
+description = invoke sphinx-build to build the HTML docs
+extras = docs
+commands =
+    sphinx-build -b html docs docs/_build/html
+
+[testenv:build-dist]
+description = build wheel and sdist
+skip_install = true
+deps =
+    build
+commands =
+    python -m build .