diff -u b/core/modules/migrate_drupal_ui/src/Tests/d6/MigrateUpgrade6Test.php b/core/modules/migrate_drupal_ui/src/Tests/d6/MigrateUpgrade6Test.php
--- b/core/modules/migrate_drupal_ui/src/Tests/d6/MigrateUpgrade6Test.php
+++ b/core/modules/migrate_drupal_ui/src/Tests/d6/MigrateUpgrade6Test.php
@@ -78,11 +78,21 @@
    */
   protected function getEntityCountsIncremental() {
     $counts = $this->getEntityCounts();
+    // Adjust the counts to include the forum and aggregator modules.
+    $counts['comment_type'] = 3;
+    $counts['field_config'] = 68;
+    $counts['field_storage_config'] = 46;
+    $counts['node_type'] = 12;
+    $counts['rdf_mapping'] = 7;
+    $counts['taxonomy_vocabulary'] = 7;
+    $counts['taxonomy_term'] = 7;
+    $counts['base_field_override'] = 35;
+    $counts['entity_form_display'] = 18;
+    $counts['entity_view_display'] = 39;
+    $counts['entity_view_mode'] = 14;
     $counts['aggregator_feed'] = 1;
     $counts['aggregator_item'] = 1;
     $counts['view'] = 14;
-    $counts['entity_view_display'] = 35;
-    $counts['entity_view_mode'] = 14;
     return $counts;
   }
 
diff -u b/core/modules/migrate_drupal_ui/src/Tests/d7/MigrateUpgrade7Test.php b/core/modules/migrate_drupal_ui/src/Tests/d7/MigrateUpgrade7Test.php
--- b/core/modules/migrate_drupal_ui/src/Tests/d7/MigrateUpgrade7Test.php
+++ b/core/modules/migrate_drupal_ui/src/Tests/d7/MigrateUpgrade7Test.php
@@ -79,11 +79,19 @@
    */
   protected function getEntityCountsIncremental() {
     $counts = $this->getEntityCounts();
+    // Adjust the counts to include the forum and aggregator modules.
+    $counts['comment_type'] = 8;
+    $counts['field_config'] = 46;
+    $counts['field_storage_config'] = 34;
+    $counts['rdf_mapping'] = 7;
+    $counts['taxonomy_term'] = 19;
+    $counts['base_field_override'] = 8;
+    $counts['entity_view_display'] = 29;
+    $counts['entity_form_display'] = 18;
+    $counts['entity_view_mode'] = 13;
     $counts['aggregator_feed'] = 1;
     $counts['aggregator_item'] = 10;
     $counts['view'] = 14;
-    $counts['entity_view_display'] = 26;
-    $counts['entity_view_mode'] = 13;
     return $counts;
   }