diff --git a/tests/src/Functional/DynamicEntityReferenceBaseTest.php b/tests/src/Functional/DynamicEntityReferenceBaseTest.php
index 90441d1..2b58e2b 100644
--- a/tests/src/Functional/DynamicEntityReferenceBaseTest.php
+++ b/tests/src/Functional/DynamicEntityReferenceBaseTest.php
@@ -85,7 +85,7 @@ class DynamicEntityReferenceBaseTest extends BrowserTestBase {
       'selection_handler' => $settings['entity_test']['handler'],
       'selection_settings_key' => $selection_settings_key,
     ))->toString();
-    $this->assertTrue(strpos((string) $input['data-autocomplete-path'], $expected_autocomplete_path) !== FALSE);
+    $this->assertTrue(strpos($input->getAttribute('data-autocomplete-path'), $expected_autocomplete_path) !== FALSE);
 
     $edit = array(
       // Ensure that an exact match on a unique label is accepted.
@@ -234,7 +234,7 @@ class DynamicEntityReferenceBaseTest extends BrowserTestBase {
       'selection_handler' => $settings['entity_test']['handler'],
       'selection_settings_key' => $selection_settings_key,
     ))->toString();
-    $this->assertTrue(strpos((string) $input['data-autocomplete-path'], $expected_autocomplete_path) !== FALSE);
+    $this->assertTrue(strpos($input->getAttribute('data-autocomplete-path'), $expected_autocomplete_path) !== FALSE);
 
     // Add some extra dynamic entity reference fields.
     $this->getSession()->getPage()->findButton('field_foobar_add_more')->click();
diff --git a/tests/src/Functional/DynamicEntityReferenceTest.php b/tests/src/Functional/DynamicEntityReferenceTest.php
index 724c511..c468459 100644
--- a/tests/src/Functional/DynamicEntityReferenceTest.php
+++ b/tests/src/Functional/DynamicEntityReferenceTest.php
@@ -245,7 +245,7 @@ class DynamicEntityReferenceTest extends BrowserTestBase {
       'selection_handler' => $settings['entity_test_label']['handler'],
       'selection_settings_key' => $selection_settings_key,
     ))->toString();
-    $this->assertTrue(strpos((string) $input['data-autocomplete-path'], $expected_autocomplete_path) !== FALSE);
+    $this->assertTrue(strpos($input->getAttribute('data-autocomplete-path'), $expected_autocomplete_path) !== FALSE);
 
     // Add some extra dynamic entity reference fields.
     $this->getSession()->getPage()->findButton('field_foobar_add_more')->click();
@@ -293,7 +293,7 @@ class DynamicEntityReferenceTest extends BrowserTestBase {
         'selection_handler' => $settings[$expected_entity_type]['handler'],
         'selection_settings_key' => $selection_settings_key,
       ))->toString();
-      $this->assertTrue(strpos((string) $input['data-autocomplete-path'], $expected_autocomplete_path) !== FALSE);
+      $this->assertTrue(strpos($input->getAttribute('data-autocomplete-path'), $expected_autocomplete_path) !== FALSE);
     }
 
     $edit = array(