Generate autoloader script for PHPUnit's own test suite's test fixture

Author: sebastianbergmann

.github/workflows/ci.yml

@@ -246,7 +246,7 @@ jobs:
           java-version: 1.8
 
       - name: Build unscoped PHAR for testing
-        run: ant unscoped-phar-snapshot
+        run: ant unscoped-phar-snapshot generate-autoloader-for-test-fixture
 
       - name: Run regular tests with unscoped PHAR
         run: ./build/artifacts/phpunit-snapshot.phar