diff --git a/comment_notify.module b/comment_notify.module
index f436342..db82a50 100644
--- a/comment_notify.module
+++ b/comment_notify.module
@@ -169,6 +169,7 @@ function _comment_notify_submit_comment_form(array &$form, FormStateInterface $f
     // anonymous. The string is built with token and their host and comment
     // identifier. It is stored and referenced, we really just need something
     // unique/unguessable. See comment_notify_unsubscribe_by_hash().
+    // @todo make the comment_notify_add_notification() generate the hash.
     $hostname = !$comment->getHostname() ? $comment->getHostname() : (isset($user->hostname) ? $user->hostname : '');
     $notify_hash = \Drupal::csrfToken()->get($hostname . $comment->id());
     comment_notify_add_notification($comment->id(), $status, $notify_hash, $comment->notified);
diff --git a/tests/src/Kernel/CommentNotifyTokenReplaceTest.php b/tests/src/Kernel/CommentNotifyTokenReplaceTest.php
new file mode 100644
index 0000000..8a2ecf6
--- /dev/null
+++ b/tests/src/Kernel/CommentNotifyTokenReplaceTest.php
@@ -0,0 +1,97 @@
+<?php
+
+namespace Drupal\Tests\comment_notify\Kernel;
+
+use Drupal\comment\Tests\CommentTestTrait;
+use Drupal\Component\Render\FormattableMarkup;
+use Drupal\Core\Render\BubbleableMetadata;
+use Drupal\node\Entity\Node;
+use Drupal\node\Entity\NodeType;
+use Drupal\Tests\system\Kernel\Token\TokenReplaceKernelTestBase;
+use Drupal\comment\Entity\Comment;
+
+/**
+ * Checks comment_notify token replacement.
+ *
+ * @group comment_notify
+ */
+class CommentNotifyTokenReplaceTest extends TokenReplaceKernelTestBase {
+
+  use CommentTestTrait;
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = ['node', 'comment', 'comment_notify'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->installConfig(['node', 'comment', 'comment_notify']);
+    $this->installSchema('comment', ['comment_entity_statistics']);
+    $this->installSchema('comment_notify', ['comment_notify']);
+
+    $node_type = NodeType::create(['type' => 'article', 'name' => 'Article']);
+    $node_type->save();
+
+    $this->addDefaultCommentField('node', 'article');
+  }
+
+  /**
+   * Tests the tokens generated by comment notify.
+   */
+  public function testNodeTokenReplacement() {
+    // Create a user, a node and a comment.
+    $account = $this->createUser();
+    /* @var $node \Drupal\node\NodeInterface */
+    $node = Node::create([
+      'type' => 'article',
+      'tnid' => 0,
+      'uid' => $account->id(),
+      'title' => 'test',
+    ]);
+    $node->save();
+    $comment = [
+      'uid' => $account->id(),
+      'entity_id' => $node->id(),
+      'entity_type' => 'node',
+      'field_name' => 'comment',
+      'subject' => 'How much wood would a woodchuck chuck',
+      'cid' => '',
+      'pid' => '',
+      'mail' => 'someone@example.com',
+    ];
+    $comment = Comment::create($comment);
+    $comment->save();
+    $notify_hash = $this->container->get('csrf_token')->get('127.0.0.1' . $comment->id());
+    comment_notify_add_notification($comment->id(), TRUE, $notify_hash, 1);
+    // Reload the comment to get its notify_hash.
+    $comment = Comment::load($comment->id());
+
+    // Generate and test tokens.
+    $tests = [];
+    $tests['[comment-subscribed:unsubscribe-url]'] = comment_notify_get_unsubscribe_url($comment);
+    $tests['[comment-subscribed:author:uid]'] = $account->id();
+
+    $base_bubbleable_metadata = BubbleableMetadata::createFromObject($comment);
+    $metadata_tests = [];
+    $metadata_tests['[comment-subscribed:unsubscribe-url]'] = $base_bubbleable_metadata;
+    $bubbleable_metadata = clone $base_bubbleable_metadata;
+    $metadata_tests['[comment-subscribed:author:uid]'] = $bubbleable_metadata->addCacheableDependency($account);
+
+    // Test to make sure that we generated something for each token.
+    $this->assertFalse(in_array(0, array_map('strlen', $tests)), 'No empty tokens generated.');
+
+    foreach ($tests as $input => $expected) {
+      $bubbleable_metadata = new BubbleableMetadata();
+      $output = $this->tokenService->replace($input, ['comment-subscribed' => $comment], ['langcode' => $this->interfaceLanguage->getId()], $bubbleable_metadata);
+      $this->assertEquals($expected, $output, new FormattableMarkup('Node token %token replaced.', ['%token' => $input]));
+      $this->assertEquals($metadata_tests[$input], $bubbleable_metadata);
+    }
+  }
+
+}