Issue #3254166: Build tests should not modify dependencies' composer.json files

tests/src/Build/CoreUpdateTest.php

@@ -213,6 +213,7 @@ class CoreUpdateTest extends UpdateTestBase {
     $assert_session->pageTextNotContains('There is a security update available for your version of Drupal.');
     $page->pressButton('Update');
     $this->waitForBatchJob();
+    print_r($page->getContent());
     $assert_session->pageTextContains('Ready to update');
     $page->pressButton('Continue');
     $this->waitForBatchJob();