diff --git a/core/modules/comment/src/Tests/CommentOrphanedTest.php b/core/modules/comment/src/Tests/CommentOrphanedTest.php
index 962e834..595826f 100644
--- a/core/modules/comment/src/Tests/CommentOrphanedTest.php
+++ b/core/modules/comment/src/Tests/CommentOrphanedTest.php
@@ -35,7 +35,10 @@ public function testDeleteOrphanedComment() {
     if (in_array('Drupal\Core\Entity\Sql\SqlEntityStorageInterface', class_implements($storage))) {
 
       // Make sure we have a comment.
-      $this->postComment($this->node, $this->randomMachineName());
+      $this->drupalLogin($this->webUser);
+      $comment_text = $this->randomMachineName();
+      $subject = $this->randomMachineName();
+      $this->postComment($this->node, $comment_text, $subject);
 
       // Mess with the comments to make them orphaned.
       $manager->clearCachedDefinitions();
@@ -46,7 +49,6 @@ public function testDeleteOrphanedComment() {
 
       // Now load and delete these comments, and implicitly test that nothing
       // breaks.
-      $storage->resetCache();
       $entities = $storage->loadMultiple($ids);
       $storage->delete($entities);
     }
diff --git a/core/modules/comment/tests/modules/comment_test/src/CommentTestSqlEntityStorage.php b/core/modules/comment/tests/modules/comment_test/src/CommentTestSqlEntityStorage.php
index f6d3a15..336b18b 100644
--- a/core/modules/comment/tests/modules/comment_test/src/CommentTestSqlEntityStorage.php
+++ b/core/modules/comment/tests/modules/comment_test/src/CommentTestSqlEntityStorage.php
@@ -15,8 +15,8 @@
 class CommentTestSqlEntityStorage extends CommentStorage {
 
   /**
-   * Intentionally makes reference data (author, parent comment) invalid, in the
-   * SQL storage backend.
+   * Intentionally makes reference data (commented entity, parent comment,
+   * author) invalid, in the SQL storage backend.
    *
    * @param array $comment_ids
    *   IDs of comments to orphan. If not provided, one comment will be taken
@@ -27,30 +27,26 @@ class CommentTestSqlEntityStorage extends CommentStorage {
    */
   public function orphanComments(array $comment_ids = array()) {
 
-    if (empty($comment_ids)) {
-      $query = $this->database->select('comment_field_data', 'c');
-      $query->addExpression('MAX(cid)');
-      $cid = $query->execute()->fetchField();
-      if ($cid) {
-        $comment_ids = array($cid);
-      }
+    // Get the maximum parent/author and set it one higher; this emulates
+    // a parent/author which has been deleted after creating.
+    $query = $this->database->select('comment_field_data', 'c');
+    $query->addExpression('MAX(cid)', 'cid_max');
+    $query->addExpression('MAX(pid)', 'pid_max');
+    $query->addExpression('MAX(uid)', 'uid_max');
+    $query->addExpression('MAX(entity_id)', 'entity_id_max');
+    $row = $query->execute()->fetchObject();
+    if (!isset($row->pid_max) && isset($row->cid_max)) {
+      $row->pid_max = $row->cid_max;
     }
 
-    if (!empty($comment_ids)) {
-      // Get the maximum parent/author and set it one higher; this emulates
-      // a parent/author which has been deleted after creating.
-      $query = $this->database->select('comment_field_data', 'c');
-      $query->addExpression('MAX(entity_id)', 'entity_id_max');
-      $query->addExpression('MAX(pid)', 'pid_max');
-      $query->addExpression('MAX(uid)', 'uid_max');
-      $row = $query->execute()->fetchObject();
-      if (!isset($row->pid_max)) {
-        $row->pid_max = 0;
-      }
+    if (empty($comment_ids) && isset($row->cid_max)) {
+      $comment_ids = array($row->cid_max);
+    }
 
+    if (!empty($comment_ids)) {
       $this->database->update('comment_field_data')
-        ->fields(array('entity_id' => $row->entity_id_max, 'pid' => $row->pid_max, 'uid' => $row->uid_max))
-        ->condition('cid', array($comment_ids))
+        ->fields(array('entity_id' => $row->entity_id_max + 1, 'pid' => $row->pid_max + 1, 'uid' => $row->uid_max + 1))
+        ->condition('cid', $comment_ids)
         ->execute();
 
       $this->resetCache();