Introduce Action to run install_requirement.py

.github/actions/install-requirement/action.yml

@@ -0,0 +1,37 @@
+name: Install Project Requirements
+description: Install requirements from a PEP 517 project
+
+inputs:
+  requirements:
+    description: "Whitespace-delimited list of project requirements to install."
+    required: true
+  project-root:
+    description: "The filesystem path to the root of the project to install from; defaults to github.workspace."
+    default: ${{ github.workspace }}
+  extra:
+    description: "Name of the optional dependencies marker; e.g. dev."
+    required: false
+    default: ""
+
+runs:
+  using: composite
+  steps:
+    - name: Checkout beeware/.github
+      uses: actions/[email protected]
+      with:
+        repository: beeware/.github
+        path: .github-beeware
+
+    - name: Install Dependencies
+      shell: bash
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install --upgrade setuptools build wheel
+
+    - name: Install Requirements
+      working-directory: ./.github-beeware/scripts
+      shell: bash
+      run: >
+        python -m install_requirement ${{ inputs.requirements }}
+          --extra "${{ inputs.extra }}"
+          --project-root "$(printf -- "%q" "${{ inputs.project-root }}")"

.github/workflows/ci.yml

@@ -184,6 +184,73 @@ jobs:
           repo: toga
           build-subdir: android
 
+  test-install-requirements:
+    name: Install Requirements
+    needs: pre-commit
+    runs-on: ${{ matrix.runner-os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        runner-os: [ macos-latest, windows-latest, ubuntu-latest ]
+    steps:
+      - name: Checkout beeware/.github
+        uses: actions/[email protected]
+        with:
+          path: repos/.github
+
+      - name: Checkout beeware/briefcase
+        uses: actions/[email protected]
+        with:
+          repository: beeware/briefcase
+
+      - name: Checkout beeware/briefcase to path
+        uses: actions/[email protected]
+        with:
+          repository: beeware/briefcase
+          path: repos/briefcase
+
+      - name: Set up Python
+        uses: actions/[email protected]
+        with:
+          python-version: "3.x"
+
+      - name: Test Install Requirements with Path
+        uses: ./repos/.github/.github/actions/install-requirement
+        with:
+          requirements: "pre-commit tox"
+          extra: "dev"
+          project-path: "repos/briefcase"
+
+      - name: Test Install Requirements
+        uses: ./repos/.github/.github/actions/install-requirement
+        with:
+          requirements: "coverage"
+          extra: "dev"
+
+      - name: Test Install Requirements
+        uses: ./repos/.github/.github/actions/install-requirement
+        with:
+          requirements: "cookiecutter"
+
+      - name: Verify Requirements Installed
+        run: |
+          if ! python -m pip list | grep tox; then
+            echo '::error::Failed to install tox'
+            exit 1
+          fi
+          if ! python -m pip list | grep pre-commit; then
+            echo '::error::Failed to install pre-commit'
+            exit 1
+          fi
+          if ! python -m pip list | grep coverage; then
+            echo '::error::Failed to install coverage'
+            exit 1
+          fi
+          if ! python -m pip list | grep cookiecutter; then
+            echo '::error::Failed to install cookiecutter'
+            exit 1
+          fi
+
   test-verify-projects-briefcase:
     name: Verify Project
     needs: [ pre-commit, test-package-python ]

scripts/install_requirement.py

@@ -7,10 +7,7 @@
 # Install one or more PEP 517 project defined requirements
 #
 # positional arguments:
-#   requirements          List of project requirements to install. Any project
-#                         requirements that start with any of these values will
-#                         be installed. For instance, including 'pytest' in this
-#                         list would install both pytest and pytest-xdist.
+#   requirements          Whitespace-delimited list of project requirements to install.
 #
 # options:
 #   -h, --help            show this help message and exit