diff --git a/src/Plugin/Filter/LinkitFilter.php b/src/Plugin/Filter/LinkitFilter.php
index cef1c6e..894ebe7 100644
--- a/src/Plugin/Filter/LinkitFilter.php
+++ b/src/Plugin/Filter/LinkitFilter.php
@@ -71,32 +71,34 @@ class LinkitFilter extends FilterBase implements ContainerFactoryPluginInterface
   public function process($text, $langcode) {
     $result = new FilterProcessResult($text);
 
-    $dom = Html::load($text);
-    $xpath = new \DOMXPath($dom);
-
-    /** @var \DOMElement $node */
-    foreach ($xpath->query('//a[@data-entity-type and @data-entity-uuid]') as $node) {
-      // Load the appropriate translation of the linked entity.
-      $entity = $this->entityRepository->loadEntityByUuid($node->getAttribute('data-entity-type'), $node->getAttribute('data-entity-uuid'));
-      $entity = $this->entityRepository->getTranslationFromContext($entity, $langcode);
-
-      // Set the appropriate href and title attributes.
-      $url = $entity->toUrl()->toString(TRUE);
-      $node->setAttribute('href', $url->getGeneratedUrl());
-      if ($this->settings['title']) {
-        $node->setAttribute('title', $entity->label());
+    if (strpos($text, 'data-entity-type') !== FALSE && strpos($text, 'data-entity-uuid') !== FALSE) {
+      $dom = Html::load($text);
+      $xpath = new \DOMXPath($dom);
+
+      /** @var \DOMElement $node */
+      foreach ($xpath->query('//a[@data-entity-type and @data-entity-uuid]') as $node) {
+        // Load the appropriate translation of the linked entity.
+        $entity = $this->entityRepository->loadEntityByUuid($node->getAttribute('data-entity-type'), $node->getAttribute('data-entity-uuid'));
+        $entity = $this->entityRepository->getTranslationFromContext($entity, $langcode);
+
+        // Set the appropriate href and title attributes.
+        $url = $entity->toUrl()->toString(TRUE);
+        $node->setAttribute('href', $url->getGeneratedUrl());
+        if ($this->settings['title']) {
+          $node->setAttribute('title', $entity->label());
+        }
+
+        // The processed text now depends on:
+        $result
+          // - the generated URL (which has undergone path & route processing)
+          ->addCacheableDependency($url)
+          // - the linked entity (whose URL and title may change)
+          ->addCacheableDependency($entity);
       }
 
-      // The processed text now depends on:
-      $result
-        // - the generated URL (which has undergone path & route processing)
-        ->addCacheableDependency($url)
-        // - the linked entity (whose URL and title may change)
-        ->addCacheableDependency($entity);
+      $result->setProcessedText(Html::serialize($dom));
     }
 
-    $result->setProcessedText(Html::serialize($dom));
-
     return $result;
   }
 
diff --git a/src/Tests/LinkitFilterTest.php b/src/Tests/LinkitFilterTest.php
new file mode 100644
index 0000000..ced056a
--- /dev/null
+++ b/src/Tests/LinkitFilterTest.php
@@ -0,0 +1,93 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\linkit\Tests\LinkitFilterTest.
+ */
+
+namespace Drupal\linkit\Tests;
+
+use Drupal\filter\FilterPluginCollection;
+
+/**
+ * Tests the Linkit filter.
+ *
+ * @group linkit
+ */
+class LinkitFilterTest extends LinkitTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = ['node', 'user'];
+
+  /**
+   * @var \Drupal\filter\Plugin\FilterInterface
+   */
+  protected $filter;
+
+  /**
+   * @inheritdoc
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    /** @var \Drupal\Component\Plugin\PluginManagerInterface $manager */
+    $manager = $this->container->get('plugin.manager.filter');
+    $bag = new FilterPluginCollection($manager, array());
+    $this->filter = $bag->get('linkit');
+  }
+
+  /**
+   * Tests the linkit filter.
+   */
+  public function testFilter() {
+    // Create a content type.
+    $this->drupalCreateContentType(['type' => 'test', 'name' => 'Test']);
+
+    $node = $this->drupalCreateNode([
+      'type' => 'test',
+      'title' => $this->randomGenerator->string()
+    ]);
+
+    $account = $this->drupalCreateUser();
+
+    // Don't automatically set the title.
+    $this->filter->setConfiguration(['settings' => ['title' => 0]]);
+
+    // Test with a node.
+    $input = '<a data-entity-type="node" data-entity-uuid="' . $node->uuid() . '">Link text</a>';
+    $expected = '<a data-entity-type="node" data-entity-uuid="' . $node->uuid() . '" href="' . $node->toUrl()->toString() . '">Link text</a>';
+    $this->assertIdentical($expected, $this->process($input)->getProcessedText());
+
+    // Test with a user.
+    $input = '<a data-entity-type="user" data-entity-uuid="' . $account->uuid() . '">Link text</a>';
+    $expected = '<a data-entity-type="user" data-entity-uuid="' . $account->uuid() . '" href="' . $account->toUrl()->toString() . '">Link text</a>';
+    $this->assertIdentical($expected, $this->process($input)->getProcessedText());
+
+    // Automatically set the title.
+    $this->filter->setConfiguration(['settings' => ['title' => 1]]);
+
+    // Test with a node.
+    $input = '<a data-entity-type="node" data-entity-uuid="' . $node->uuid() . '">Link text</a>';
+    $expected = '<a data-entity-type="node" data-entity-uuid="' . $node->uuid() . '" href="' . $node->toUrl()->toString() . '" title="' . $node->label() . '">Link text</a>';
+    $this->assertIdentical($expected, $this->process($input)->getProcessedText());
+
+    // Test with a user.
+    $input = '<a data-entity-type="user" data-entity-uuid="' . $account->uuid() . '">Link text</a>';
+    $expected = '<a data-entity-type="user" data-entity-uuid="' . $account->uuid() . '" href="' . $account->toUrl()->toString() . '" title="' . $account->label() . '">Link text</a>';
+    $this->assertIdentical($expected, $this->process($input)->getProcessedText());
+  }
+
+  /**
+   * Test helper method that wraps the filter process method.
+   *
+   * @see \Drupal\filter\Plugin\FilterInterface::process
+   */
+  private function process($input, $langcode = 'und') {
+    return $this->filter->process($input, $langcode);
+  }
+
+}