CI: Require PHPUnit 7.5 for WP < 5.9

See https://make.wordpress.org/core/2021/09/27/changes-to-the-wordpress-core-php-test-suite/#integration-tests-ci-changes - PHPUnit 9 removed a `PHPUnit\Util\Getopt` class, but the [fix](https://core.trac.wordpress.org/changeset/51570/) wasn't applied to WP until 5.9.
Automattic · Jul 24, 2023 · dd6e0d1 · dd6e0d1
1 parent b38e1e5
commit dd6e0d1
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/.github/workflows/integrate.yml b/.github/workflows/integrate.yml
@@ -44,6 +44,11 @@ jobs:
           ini-values: ${{ matrix.ini-values }}
           coverage: ${{ matrix.coverage }}
 
+      - name: Install PHPUnit 7.x for WP < 5.9
+        if: ${{ matrix.wordpress < 5.9 }}
+        # Ignore platform requirements, so that PHPUnit 7.5 can be installed on PHP 8.0 (and above).
+        run: composer require --dev "phpunit/phpunit:^7.5" --ignore-platform-reqs
+
       - name: Install Composer dependencies
         uses: ramsey/composer-install@v2
         with: