Add workflow for building and checking package metadata (#3)

.github/workflows/python-test-build.yaml

@@ -0,0 +1,27 @@
+on:
+  workflow_call:
+    inputs:
+      requirements_file:
+        type: "string"
+        required: false
+        default: "setup.cfg"
+
+jobs:
+  build-and-check:
+    name: Build and check package metadata
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+    - name: pip cache
+      uses: actions/cache@v2
+      with:
+        path: ~/.cache/pip
+        key: ${{ runner.os }}-pip-${{ hashFiles(inputs.requirements_file) }}
+        restore-keys: ${{ runner.os }}-pip
+    - name: Install dependencies
+      run: python3 -m pip install --upgrade build twine
+    - name: Build
+      run: python3 -m build --sdist --wheel .
+    - name: Check package metadata
+      run: twine check --strict dist/*

README.md

@@ -44,3 +44,24 @@ jobs:
     with:
       python-version: "3.10"
 ```
+
+### `python-test-build`
+
+A reusable workflow for verifying Python package metadata.
+
+#### Example usage
+
+```yaml
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  check-build:
+    name: Check packaging
+    uses: less-action/reusables/.github/workflows/python-test-build.yaml@v2
+```