diff --git a/core/modules/file/tests/src/Functional/Formatter/FileAudioFormatterTest.php b/core/modules/file/tests/src/Functional/Formatter/FileAudioFormatterTest.php
index ce7c4059b2..94342d6a83 100644
--- a/core/modules/file/tests/src/Functional/Formatter/FileAudioFormatterTest.php
+++ b/core/modules/file/tests/src/Functional/Formatter/FileAudioFormatterTest.php
@@ -35,9 +35,9 @@ public function testRender() {
 
     $this->drupalGet($entity->url());
 
-    $file_url = file_create_url($file->getFileUri());
+    $file_url = file_url_transform_relative(file_create_url($file->getFileUri()));
     $this->assertSession()->elementExists('css', 'audio[controls="controls"]');
-    $this->assertSession()->elementExists('css', "audio > source[src='$file_url'][type='audio/mpeg']");
+    $this->assertSession()->elementExists('css', "audio > source[src*='$file_url'][type='audio/mpeg']");
   }
 
 }
diff --git a/core/modules/file/tests/src/Functional/Formatter/FileMediaFormatterTestBase.php b/core/modules/file/tests/src/Functional/Formatter/FileMediaFormatterTestBase.php
index 2fbce8475d..8e82a754fd 100644
--- a/core/modules/file/tests/src/Functional/Formatter/FileMediaFormatterTestBase.php
+++ b/core/modules/file/tests/src/Functional/Formatter/FileMediaFormatterTestBase.php
@@ -9,10 +9,11 @@
 use Drupal\Tests\BrowserTestBase;
 
 /**
- * @coversDefaultClass \Drupal\file\Plugin\Field\FieldFormatter\FileAudioFormatter
+ * Provides methods specifically for testing File module's media formatter's.
+ *
  * @group file
  */
-class FileMediaFormatterTestBase extends BrowserTestBase {
+abstract class FileMediaFormatterTestBase extends BrowserTestBase {
 
   /**
    * The field name.
@@ -47,17 +48,25 @@ protected function setUp() {
     $this->drupalLogin($this->drupalCreateUser(['view test entity']));
   }
 
+  /**
+   * Creates a file field and set's the correct formatter.
+   *
+   * @param string $formatter
+   *   The formatter ID.
+   * @param string $file_extionsions
+   *   The file extensions of the new field.
+   */
   protected function createMediaField($formatter, $file_extionsions) {
 
     $entityType = $bundle = 'entity_test';
     $this->fieldName = Unicode::strtolower($this->randomMachineName());
 
-    FieldStorageConfig::create(array(
+    FieldStorageConfig::create([
       'entity_type' => $entityType,
       'field_name' => $this->fieldName,
       'type' => 'file',
       'cardinality' => FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED,
-    ))->save();
+    ])->save();
     FieldConfig::create([
       'entity_type' => $entityType,
       'field_name' => $this->fieldName,
diff --git a/core/modules/file/tests/src/Functional/Formatter/FileVideoFormatterTest.php b/core/modules/file/tests/src/Functional/Formatter/FileVideoFormatterTest.php
index cb55890019..da67c78f1a 100644
--- a/core/modules/file/tests/src/Functional/Formatter/FileVideoFormatterTest.php
+++ b/core/modules/file/tests/src/Functional/Formatter/FileVideoFormatterTest.php
@@ -35,9 +35,9 @@ public function testRender() {
 
     $this->drupalGet($entity->url());
 
-    $file_url = file_create_url($file->getFileUri());
+    $file_url = file_url_transform_relative(file_create_url($file->getFileUri()));
     $this->assertSession()->elementExists('css', 'video[controls="controls"]');
-    $this->assertSession()->elementExists('css', "video > source[src='$file_url'][type='video/mp4']");
+    $this->assertSession()->elementExists('css', "video > source[src*='$file_url'][type='video/mp4']");
   }
 
 }