diff --git a/core/modules/file/tests/src/Kernel/FileUriItemTest.php b/core/modules/file/tests/src/Kernel/FileUriItemTest.php
new file mode 100644
index 0000000000..f2439da5f0
--- /dev/null
+++ b/core/modules/file/tests/src/Kernel/FileUriItemTest.php
@@ -0,0 +1,35 @@
+<?php
+
+namespace Drupal\Tests\file\Kernel;
+use Drupal\file\Entity\File;
+
+/**
+ * Custom URI field item test.
+ *
+ * @group file
+ */
+class FileUriItemTest extends FileManagedUnitTestBase {
+
+  /**
+   * Tests the file entity override of the Url 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);
+    $this->assertSame(file_create_url($uri), $file->uri->url);
+  }
+
+}
diff --git a/core/modules/file/tests/src/Unit/FileUrlTest.php b/core/modules/file/tests/src/Unit/FileUrlTest.php
new file mode 100644
index 0000000000..ec0f22ce6f
--- /dev/null
+++ b/core/modules/file/tests/src/Unit/FileUrlTest.php
@@ -0,0 +1,85 @@
+<?php
+
+namespace Drupal\Tests\file\Unit;
+
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Field\FieldItemInterface;
+use Drupal\Core\TypedData\DataDefinitionInterface;
+use Drupal\file\FileUrl;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @coversDefaultClass \Drupal\file\FileUrl
+ *
+ * @group file
+ */
+class FileUrlTest extends UnitTestCase {
+
+  /**
+   * The test URL to use.
+   *
+   * @var string
+   */
+  protected $testUrl = 'https://localhost.test';
+
+  /**
+   * @covers ::getValue
+   */
+  public function testGetValue() {
+    $entity = $this->prophesize(EntityInterface::class);
+    $entity->url()
+      ->willReturn($this->testUrl);
+
+    $parent = $this->prophesize(FieldItemInterface::class);
+    $parent->getEntity()
+      ->shouldBeCalledTimes(1)
+      ->willReturn($entity->reveal());
+
+    $definition = $this->prophesize(DataDefinitionInterface::class);
+
+    $typed_data = new FileUrl($definition->reveal(), 'test', $parent->reveal());
+
+    $this->assertSame($this->testUrl, $typed_data->getValue());
+    // Do this a second time to confirm the same value is returned but the value
+    // isn't retrieved from the parent entity again.
+    $this->assertSame($this->testUrl, $typed_data->getValue());
+  }
+
+  /**
+   * @covers ::setValue
+   */
+  public function testSetValue() {
+    $parent = $this->prophesize(FieldItemInterface::class);
+    $parent->onChange('test')
+      ->shouldBeCalled();
+
+    $definition = $this->prophesize(DataDefinitionInterface::class);
+    $typed_data = new FileUrl($definition->reveal(), 'test', $parent->reveal());
+
+    // Setting the value should explicitly should mean the parent entity is
+    // never called into.
+    $typed_data->setValue($this->testUrl);
+
+    $this->assertSame($this->testUrl, $typed_data->getValue());
+    // Do this a second time to confirm the same value is returned but the value
+    // isn't retrieved from the parent entity again.
+    $this->assertSame($this->testUrl, $typed_data->getValue());
+  }
+
+  /**
+   * @covers ::setValue
+   */
+  public function testSetValueNoNotify() {
+    $parent = $this->prophesize(FieldItemInterface::class);
+    $parent->onChange('test')
+      ->shouldNotBeCalled();
+
+    $definition = $this->prophesize(DataDefinitionInterface::class);
+    $typed_data = new FileUrl($definition->reveal(), 'test', $parent->reveal());
+
+    // Setting the value should explicitly should mean the parent entity is
+    // never called into.
+    $typed_data->setValue($this->testUrl, FALSE);
+  }
+
+}