--- /dev/null
+<?php
+
+namespace Drupal\Tests\file\Kernel;
+
+use Drupal\file\Entity\File;
+
+/**
+ * File URI field item test.
+ *
+ * @group file
+ *
+ * @see \Drupal\file\Plugin\Field\FieldType\FileUriItem
+ * @see \Drupal\file\FileUrl
+ */
+class FileUriItemTest extends FileManagedUnitTestBase {
+
+ /**
+ * Tests the file entity override of the URI field.
+ */
+ public function testCustomFileUriField() {
+ $uri = 'public://druplicon.txt';
+
+ // Create a new file entity.
+ $file = File::create([
+ 'uid' => 1,
+ 'filename' => 'druplicon.txt',
+ 'uri' => $uri,
+ 'filemime' => 'text/plain',
+ 'status' => FILE_STATUS_PERMANENT,
+ ]);
+ file_put_contents($file->getFileUri(), 'hello world');
+
+ $file->save();
+
+ $this->assertSame($uri, $file->uri->value);
+ $expected_url = base_path() . $this->siteDirectory . '/files/druplicon.txt';
+ $this->assertSame($expected_url, $file->uri->url);
+ }
+
+}