ci: add integration test workflow

Adds the missing integration test workflow to run PHPUnit tests
against WordPress. Tests against WP 6.4 + PHP 7.4 (minimum) and
WP master + PHP latest.

Uses the standard workflow structure consistent with other
Automattic plugins.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: GaryJones

.github/workflows/integration.yml

@@ -0,0 +1,79 @@
+name: Run PHPUnit
+
+on:
+  push:
+    branches:
+      - develop
+      - trunk
+    paths:
+      - '.github/workflows/integration.yml'
+      - '**.php'
+      - 'phpunit.xml.dist'
+      - 'composer.json'
+  pull_request:
+    paths:
+      - '.github/workflows/integration.yml'
+      - '**.php'
+      - 'phpunit.xml.dist'
+      - 'composer.json'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: WP ${{ matrix.wordpress }} on PHP ${{ matrix.php }}
+    runs-on: ubuntu-latest
+
+    env:
+      WP_ENV_CORE: WordPress/WordPress#${{ matrix.wordpress }}
+
+    strategy:
+      matrix:
+        include:
+          # Check lowest supported WP version, with the lowest supported PHP.
+          - wordpress: '6.4'
+            php: '7.4'
+          # Check latest WP with the latest PHP.
+          - wordpress: 'master'
+            php: 'latest'
+      fail-fast: false
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
+
+      - name: Install wordpress environment
+        run: npm install -g @wordpress/env
+
+      - name: Setup PHP ${{ matrix.php }}
+        uses: shivammathur/setup-php@44454db4f0199b8b9685a5d763dc37cbf79108e1 # 2.36.0
+        with:
+          php-version: ${{ matrix.php }}
+          tools: composer
+
+      - name: Install Composer dependencies
+        uses: ramsey/composer-install@3cf229dc2919194e9e36783941438d17239e8520 # 3.1.1
+
+      - name: Setup problem matchers for PHP
+        run: echo "::add-matcher::${{ runner.tool_cache }}/php.json"
+
+      - name: Setup problem matchers for PHPUnit
+        run: echo "::add-matcher::${{ runner.tool_cache }}/phpunit.json"
+
+      - name: Setup wp-env
+        run: wp-env start
+
+      - name: Run integration tests (single site)
+        run: composer test:integration
+
+      - name: Run integration tests (multisite)
+        run: composer test:integration-ms

composer.json

@@ -47,8 +47,8 @@
 		"lint": "@php ./vendor/php-parallel-lint/php-parallel-lint/parallel-lint . -e php --exclude vendor --exclude .git",
 		"lint-ci": "@php ./vendor/php-parallel-lint/php-parallel-lint/parallel-lint . -e php --exclude vendor --exclude .git --checkstyle",
 		"test:unit": "@php ./vendor/bin/phpunit --testsuite Unit",
-		"test:integration": "wp-env run tests-cli --env-cwd=wp-content/plugins/rewrite-rules-inspector ./vendor/bin/phpunit --testsuite WP_Tests",
-		"test:integration-ms": "wp-env run tests-cli --env-cwd=wp-content/plugins/rewrite-rules-inspector /bin/bash -c 'WP_MULTISITE=1 ./vendor/bin/phpunit --testsuite WP_Tests'"
+		"test:integration": "wp-env run tests-cli --env-cwd=wp-content/plugins/Rewrite-Rules-Inspector ./vendor/bin/phpunit --testsuite WP_Tests",
+		"test:integration-ms": "wp-env run tests-cli --env-cwd=wp-content/plugins/Rewrite-Rules-Inspector /bin/bash -c 'WP_MULTISITE=1 ./vendor/bin/phpunit --testsuite WP_Tests'"
 	},
 	"scripts-descriptions": {
 		"coverage": "Run tests with code coverage reporting",

tests/Integration/bootstrap.php

@@ -5,23 +5,46 @@
  * @package Automattic\RewriteRulesInspector\Tests\Integration
  */
 
+namespace Automattic\RewriteRulesInspector\Tests\Integration;
+
 use Yoast\WPTestUtils\WPIntegration;
 
-// Load Composer autoloader.
-require_once dirname( __DIR__, 2 ) . '/vendor/autoload.php';
+$vendor_dir = dirname( __DIR__, 2 ) . '/vendor';
+
+// Load the Yoast WP test utils bootstrap functions.
+require_once $vendor_dir . '/yoast/wp-test-utils/src/WPIntegration/bootstrap-functions.php';
+
+$_tests_dir = WPIntegration\get_path_to_wp_test_dir();
+
+if ( empty( $_tests_dir ) ) {
+	echo 'ERROR: Could not find WordPress test library directory.' . PHP_EOL;
+	echo 'Make sure wp-env is running: npm run wp-env start' . PHP_EOL;
+	exit( 1 );
+}
 
-// Get access to tests_add_filter() function.
-require_once getenv( 'WP_PHPUNIT__DIR' ) . '/includes/functions.php';
+// Give access to tests_add_filter() function.
+require_once $_tests_dir . '/includes/functions.php';
 
 /**
  * Manually load the plugin being tested.
  */
-tests_add_filter(
+\tests_add_filter(
 	'muplugins_loaded',
 	static function (): void {
 		require dirname( __DIR__, 2 ) . '/rewrite-rules-inspector.php';
 	}
 );
 
-// Bootstrap WordPress.
-WPIntegration\bootstrap_it();
+// Make sure the Composer autoload file has been generated.
+WPIntegration\check_composer_autoload_exists();
+
+// Start up the WP testing environment.
+require $_tests_dir . '/includes/bootstrap.php';
+
+/*
+ * Register the custom autoloader to overload the PHPUnit MockObject classes when running on PHP 8.
+ *
+ * This function has to be called _last_, after the WP test bootstrap to make sure it registers
+ * itself in FRONT of the Composer autoload (which also prepends itself to the autoload queue).
+ */
+WPIntegration\register_mockobject_autoloader();

tests/bootstrap.php

@@ -5,14 +5,33 @@
  * @package Automattic\RewriteRulesInspector\Tests
  */
 
-// Detect which testsuite is being run based on environment variable or default.
-$testsuite = getenv( 'TESTSUITE' );
-if ( ! $testsuite ) {
-	$testsuite = 'Unit';
+// Check for a `--testsuite WP_Tests` or `--testsuite=WP_Tests` arg when calling phpunit,
+// and use it to conditionally load up WordPress.
+$argv_local     = $GLOBALS['argv'] ?? [];
+$key            = (int) array_search( '--testsuite', $argv_local, true );
+$is_integration = false;
+
+// Check for --testsuite WP_Tests (two separate args).
+if ( $key && isset( $argv_local[ $key + 1 ] ) && 'WP_Tests' === $argv_local[ $key + 1 ] ) {
+	$is_integration = true;
 }
 
-if ( 'Unit' === $testsuite ) {
-	require_once __DIR__ . '/Unit/bootstrap.php';
-} else {
+// Check for --testsuite=WP_Tests (single arg with equals).
+foreach ( $argv_local as $arg ) {
+	if ( '--testsuite=WP_Tests' === $arg ) {
+		$is_integration = true;
+		break;
+	}
+}
+
+// Also check for TESTSUITE environment variable as fallback.
+$testsuite_env = getenv( 'TESTSUITE' );
+if ( 'WP_Tests' === $testsuite_env || 'integration' === $testsuite_env ) {
+	$is_integration = true;
+}
+
+if ( $is_integration ) {
 	require_once __DIR__ . '/Integration/bootstrap.php';
+} else {
+	require_once __DIR__ . '/Unit/bootstrap.php';
 }