internal: add phpunit tests

.github/workflows/phpunit-test.yml

@@ -0,0 +1,90 @@
+name: PHPUnit Test Runner
+
+on:
+  workflow_call:
+    inputs:
+      php-version:
+        required: false
+        type: string
+        default: '8.1'
+        description: 'PHP version to test against'
+
+jobs:
+  phpunit-test:
+    name: PHPUnit tests (PHP ${{ inputs.php-version }})
+    runs-on: ubuntu-22.04
+
+    services:
+      mysql:
+        image: mysql:8.0
+        env:
+          MYSQL_ROOT_PASSWORD: root
+          MYSQL_DATABASE: wordpress_test
+        ports:
+          - 3306:3306
+        options: --health-cmd="mysqladmin ping" --health-interval=10s --health-timeout=5s --health-retries=3
+
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@v4
+
+      - name: Set up PHP
+        uses: codesnippetspro/setup-php@v2
+        with:
+          php-version: ${{ inputs.php-version }}
+
+      - name: Compute dependency hash
+        id: deps-hash
+        run: |
+          set -euo pipefail
+          tmpfile=$(mktemp)
+          if [ -f "src/composer.lock" ]; then
+            cat "src/composer.lock" >> "$tmpfile"
+          fi
+          if [ -s "$tmpfile" ]; then
+            deps_hash=$(shasum -a 1 "$tmpfile" | awk '{print $1}' | cut -c1-8)
+          else
+            deps_hash=$(echo "${GITHUB_SHA:-unknown}" | cut -c1-8)
+          fi
+          echo "deps_hash=$deps_hash" >> "$GITHUB_OUTPUT"
+
+      - name: Get Composer cache
+        id: composer-cache
+        uses: actions/cache/restore@v4
+        with:
+          path: src/vendor
+          key: ${{ runner.os }}-php-${{ inputs.php-version }}-composer-${{ steps.deps-hash.outputs.deps_hash }}
+          restore-keys: |
+            ${{ runner.os }}-php-${{ inputs.php-version }}-composer-
+
+      - name: Install Composer dependencies
+        if: steps.composer-cache.outputs.cache-hit != 'true'
+        run: |
+          cd src
+          composer install --no-progress --prefer-dist --optimize-autoloader
+
+      - name: Save Composer cache
+        if: steps.composer-cache.outputs.cache-hit != 'true'
+        uses: actions/cache/save@v4
+        with:
+          path: src/vendor
+          key: ${{ runner.os }}-php-${{ inputs.php-version }}-composer-${{ steps.deps-hash.outputs.deps_hash }}
+
+      - name: Install WordPress test suite
+        run: |
+          bash tests/install-wp-tests.sh wordpress_test root root 127.0.0.1:3306 latest true
+
+      - name: Run PHPUnit tests
+        run: |
+          cd src
+          vendor/bin/phpunit -c ../phpunit.xml --testdox
+
+      - uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: phpunit-test-results-php-${{ inputs.php-version }}
+          path: |
+            .phpunit.result.cache
+          if-no-files-found: ignore
+          retention-days: 2
+

.github/workflows/phpunit.yml

@@ -0,0 +1,79 @@
+name: "(Test): PHPUnit"
+
+on:
+  pull_request:
+    types: [labeled, synchronize, opened, reopened]
+  push:
+    branches:
+      - 'core'
+      - 'pro'
+    paths-ignore:
+      - '**.md'
+      - '**.txt'
+      - '.gitignore'
+      - 'docs/**'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pull-requests: read
+  actions: read
+
+concurrency:
+  group: phpunit-${{ github.event_name }}-${{ github.event_name == 'pull_request' && github.event.pull_request.number || github.ref }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
+jobs:
+  phpunit-php-7-4:
+    if: github.event_name != 'pull_request' || contains(github.event.pull_request.labels.*.name, 'run-tests')
+    uses: ./.github/workflows/phpunit-test.yml
+    with:
+      php-version: '7.4'
+
+  phpunit-php-8-0:
+    if: github.event_name != 'pull_request' || contains(github.event.pull_request.labels.*.name, 'run-tests')
+    uses: ./.github/workflows/phpunit-test.yml
+    with:
+      php-version: '8.0'
+
+  phpunit-php-8-1:
+    if: github.event_name != 'pull_request' || contains(github.event.pull_request.labels.*.name, 'run-tests')
+    uses: ./.github/workflows/phpunit-test.yml
+    with:
+      php-version: '8.1'
+
+  phpunit-php-8-2:
+    if: github.event_name != 'pull_request' || contains(github.event.pull_request.labels.*.name, 'run-tests')
+    uses: ./.github/workflows/phpunit-test.yml
+    with:
+      php-version: '8.2'
+
+  phpunit-php-8-3:
+    if: github.event_name != 'pull_request' || contains(github.event.pull_request.labels.*.name, 'run-tests')
+    uses: ./.github/workflows/phpunit-test.yml
+    with:
+      php-version: '8.3'
+
+  test-result:
+    needs: [phpunit-php-7-4, phpunit-php-8-0, phpunit-php-8-1, phpunit-php-8-2, phpunit-php-8-3]
+    if: always() && (needs.phpunit-php-7-4.result != 'skipped' || needs.phpunit-php-8-0.result != 'skipped' || needs.phpunit-php-8-1.result != 'skipped' || needs.phpunit-php-8-2.result != 'skipped' || needs.phpunit-php-8-3.result != 'skipped')
+    runs-on: ubuntu-22.04
+    name: PHPUnit - Test Results Summary
+    steps:
+      - name: Test status summary
+        run: |
+          echo "PHP 7.4: ${{ needs.phpunit-php-7-4.result }}"
+          echo "PHP 8.0: ${{ needs.phpunit-php-8-0.result }}"
+          echo "PHP 8.1: ${{ needs.phpunit-php-8-1.result }}"
+          echo "PHP 8.2: ${{ needs.phpunit-php-8-2.result }}"
+          echo "PHP 8.3: ${{ needs.phpunit-php-8-3.result }}"
+
+      - name: Check overall status
+        if: |
+          (needs.phpunit-php-7-4.result != 'success' && needs.phpunit-php-7-4.result != 'skipped') ||
+          (needs.phpunit-php-8-0.result != 'success' && needs.phpunit-php-8-0.result != 'skipped') ||
+          (needs.phpunit-php-8-1.result != 'success' && needs.phpunit-php-8-1.result != 'skipped') ||
+          (needs.phpunit-php-8-2.result != 'success' && needs.phpunit-php-8-2.result != 'skipped') ||
+          (needs.phpunit-php-8-3.result != 'success' && needs.phpunit-php-8-3.result != 'skipped')
+        run: exit 1
+

.gitignore

@@ -12,6 +12,10 @@ node_modules/
 npm-debug.log
 .sass-cache/
 
+# PHPUnit
+.phpunit.result.cache
+/coverage/
+
 # Playwright
 playwright-report/
 test-results/

package.json

@@ -8,6 +8,8 @@
     "test": "tests"
   },
   "scripts": {
+    "test:php": "cd src && vendor/bin/phpunit -c ../phpunit.xml",
+    "test:php:watch": "npm run test:php -- --testdox",
     "test:playwright": "playwright test -c tests/playwright/playwright.config.ts",
     "test:playwright:debug": "npm run test:playwright -- --debug",
     "test:playwright:ui": "npm run test:playwright -- --ui",

src/composer.json

@@ -37,7 +37,9 @@
     "require-dev": {
         "wp-coding-standards/wpcs": "^3.1",
         "phpcompatibility/phpcompatibility-wp": "^2.1",
-        "dealerdirect/phpcodesniffer-composer-installer": "^1.0"
+        "dealerdirect/phpcodesniffer-composer-installer": "^1.0",
+        "phpunit/phpunit": "^9.6",
+        "yoast/phpunit-polyfills": "^2.0"
     },
     "config": {
         "platform": {