feat: add re-usable GitHub action

Define a re-usable GitHub action based on the existing workflow file.

This action can be used in other repositories (running schedules pipelines)
to repeatedly and regularly run the WordPress test suite on remote hosts.

Author: martin-helmich

.github/actions/wordpress-host-test/action.yml

@@ -0,0 +1,136 @@
+name: WordPress Host Test
+description: >
+  Run the WordPress Host Test on a remote system reachable via SSH
+
+inputs:
+  report-api-key:
+    description: >
+      API key for reporting test results back to wordpress.org; if omitted,
+      test result reporting will be skipped.
+    required: false
+  remote-test-dir:
+    description: >
+      Remote directory in which tests will be run
+    required: true
+  database-host:
+    description: >
+      Database host for running the unit tests
+    required: true
+  database-user:
+    description: >
+      Database user for running the unit tests
+    required: true
+  database-password:
+    description: >
+      Database password for running the unit tests
+    required: true
+  database-name:
+    description: >
+      Database name for running the unit tests
+    required: true
+  ssh-connect:
+    description: >
+      SSH connection string (in the format username@host) for connecting to the
+      hosting environment under test.
+    required: true
+  ssh-private-key:
+    description: >
+      A base64-encoded SSH private key.
+    required: true
+  test-filter:
+    description: A regular expression to filter tests that should be run.
+    default: '.*'
+runs:
+  using: "composite"
+  steps:  
+    - name: Checkout repository
+      uses: actions/checkout@v4
+      with:
+        repository: WordPress/phpunit-test-runner
+        path: runner
+
+    - name: Set up PHP
+      uses: shivammathur/setup-php@cf4cade2721270509d5b1c766ab3549210a39a2a # v2.33.0
+      with:
+        php-version: '8.4'
+        coverage: none
+
+    - name: Install NodeJS
+      uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
+      with:
+        node-version: 20
+    
+    - name: Prepare SSH private key
+      shell: bash
+      if: ${{ inputs.ssh-private-key }}
+      run: |
+        mkdir -p ~/.ssh
+        echo '${{ inputs.ssh-private-key }}' | base64 -d > ~/.ssh/id_rsa
+        chmod 600 ~/.ssh/id_rsa
+    
+    - name: Test SSH connectivity
+      shell: bash
+      run: |
+        ssh -o StrictHostKeyChecking=no ${{ inputs.ssh-connect }} whoami
+
+    - name: Prepare environment
+      env:
+        WPT_PREPARE_DIR: /tmp/wp-tests
+        WPT_TEST_DIR: ${{ inputs.remote-test-dir }}
+        WPT_DB_NAME: ${{ inputs.database-name }}
+        WPT_DB_USER: ${{ inputs.database-user }}
+        WPT_DB_PASSWORD: ${{ inputs.database-password }}
+        WPT_DB_HOST:  ${{ inputs.database-host }}
+        WPT_SSH_CONNECT: ${{ inputs.ssh-connect }}
+      run: php prepare.php
+      shell: bash
+      working-directory: ./runner
+
+    - name: Run unit tests
+      run: php test.php
+      continue-on-error: true
+      shell: bash
+      working-directory: ./runner
+      env:
+        WPT_PREPARE_DIR: /tmp/wp-tests
+        WPT_TEST_DIR: ${{ inputs.remote-test-dir }}
+        WPT_DB_NAME: ${{ inputs.database-name }}
+        WPT_DB_USER: ${{ inputs.database-user }}
+        WPT_DB_PASSWORD: ${{ inputs.database-password }}
+        WPT_DB_HOST:  ${{ inputs.database-host }}
+        WPT_SSH_CONNECT: ${{ inputs.ssh-connect }}
+        WPT_PHPUNIT_CMD: >
+          cd ${{ inputs.remote-test-dir }} && 
+          ./vendor/phpunit/phpunit/phpunit 
+          --dont-report-useless-tests 
+          -c tests/phpunit/multisite.xml
+          --filter '${{ inputs.test-filter }}'
+
+    - name: Report the results
+      run: php report.php
+      continue-on-error: true
+      if: ${{ inputs.report-api-key }}
+      shell: bash
+      working-directory: ./runner
+      env:
+        WPT_REPORT_API_KEY: ${{ inputs.report-api-key }}
+        WPT_PREPARE_DIR: /tmp/wp-tests
+        WPT_TEST_DIR: ${{ inputs.remote-test-dir }}
+        WPT_DB_NAME: ${{ inputs.database-name }}
+        WPT_DB_USER: ${{ inputs.database-user }}
+        WPT_DB_PASSWORD: ${{ inputs.database-password }}
+        WPT_DB_HOST:  ${{ inputs.database-host }}
+        WPT_SSH_CONNECT: ${{ inputs.ssh-connect }}
+
+    - name: Cleanup
+      run: php cleanup.php
+      shell: bash
+      working-directory: ./runner
+      env:
+        WPT_PREPARE_DIR: /tmp/wp-tests
+        WPT_TEST_DIR: ${{ inputs.remote-test-dir }}
+        WPT_DB_NAME: ${{ inputs.database-name }}
+        WPT_DB_USER: ${{ inputs.database-user }}
+        WPT_DB_PASSWORD: ${{ inputs.database-password }}
+        WPT_DB_HOST:  ${{ inputs.database-host }}
+        WPT_SSH_CONNECT: ${{ inputs.ssh-connect }}