diff --git a/core/modules/migrate_drupal_ui/tests/src/Functional/MigrateUpgradeTestBase.php b/core/modules/migrate_drupal_ui/tests/src/Functional/MigrateUpgradeTestBase.php
index d125c865ad..6bb66660fa 100644
--- a/core/modules/migrate_drupal_ui/tests/src/Functional/MigrateUpgradeTestBase.php
+++ b/core/modules/migrate_drupal_ui/tests/src/Functional/MigrateUpgradeTestBase.php
@@ -181,15 +181,12 @@ public function testMigrateUpgrade() {
     \Drupal::service('module_installer')->install(['forum']);
     \Drupal::service('module_installer')->install(['book']);
 
-    // Install aggregator module.
-    \Drupal::service('module_installer')->install(['aggregator']);
-
     // Test incremental migration.
     $this->createContentPostUpgrade();
 
     // Need to update available and missing path lists.
     $this->drupalGet('/upgrade');
-    $session->responseContains('An upgrade has already been performed on this site. To perform a new migration, create a clean and empty new install of Drupal 8. Rollbacks are not yet supported through the user interface.');
+    $session->pageTextContains('An upgrade has already been performed on this site. To perform a new migration, create a clean and empty new install of Drupal 8. Rollbacks are not yet supported through the user interface.');
     $this->drupalPostForm(NULL, [], t('Import new configuration and content from old site'));
     $session->pageTextContains('WARNING: Content may be overwritten on your new site.');
     $session->pageTextContains('There is conflicting content of these types:');
@@ -265,7 +262,7 @@ protected function translatePostValues(array $values) {
   abstract protected function getMissingPaths();
 
   /**
-   * Gets the expected number of entities per entity type after incremental.
+   * Gets expected number of entities per entity after incremental migration.
    *
    * @return int[]
    *   An array of expected counts keyed by entity type ID.