diff --git a/core/tests/Drupal/Tests/Core/Field/FieldFilteredStringTest.php b/core/tests/Drupal/Tests/Core/Field/FieldFilteredStringTest.php
index 0289bd7..0ca4f1c 100644
--- a/core/tests/Drupal/Tests/Core/Field/FieldFilteredStringTest.php
+++ b/core/tests/Drupal/Tests/Core/Field/FieldFilteredStringTest.php
@@ -36,25 +36,22 @@ public function testCreate($string, $expected, $instance_of_check) {
   public function providerTestCreate() {
     $data = [];
     $data[] = ['', '', FALSE];
-    $data[] = ['teststring', 'teststring', TRUE];
-
+    // Certain tags are filtered.
+    $data[] = ['<script>teststring</script>', 'teststring', TRUE];
+    // Certain tags are not filtered.
+    $data[] = ['<em>teststring</em>', '<em>teststring</em>', TRUE];
+    // HTML will be normalised.
+    $data[] = ['<em>teststring', '<em>teststring</em>', TRUE];
+
+    // Even safe strings will be escaped.
     $safe_string = $this->prophesize(SafeStringInterface::class);
-    $safe_string->__toString()->willReturn('teststring');
+    $safe_string->__toString()->willReturn('<script>teststring</script>');
     $data[] = [$safe_string->reveal(), 'teststring', TRUE];
 
     return $data;
   }
 
   /**
-   * @covers: ::allowedTags
-   */
-  public function testAllowedTags() {
-    $expected = ['a', 'b', 'big', 'code', 'del', 'em', 'i', 'ins',  'pre', 'q', 'small', 'span', 'strong', 'sub', 'sup', 'tt', 'ol', 'ul', 'li', 'p', 'br', 'img'];
-
-    $this->assertSame($expected, FieldFilteredString::allowedTags());
-  }
-
-  /**
    * @covers: ::displayAllowedTags
    */
   public function testdisplayAllowedTags() {