--- /dev/null
+<?php
+
+namespace Drupal\Tests\media\FunctionalJavascript;
+
+use Drupal\media\Entity\Media;
+use Drupal\media\Entity\MediaType;
+
+/**
+ * Tests the file media source.
+ *
+ * @group media
+ */
+class MediaSourceFileTest extends MediaSourceTestBase {
+
+ /**
+ * {@inheritdoc}
+ */
+ protected function setUp() {
+ parent::setUp();
+
+ // We need to test without any default configuration in place.
+ // @TODO: Remove this as part of https://www.drupal.org/node/2883813.
+ MediaType::load('file')->delete();
+ }
+
+ /**
+ * Tests the file media source.
+ */
+ public function testMediaFileSource() {
+ $media_type_id = 'test_media_file_type';
+ $source_field_id = 'field_media_file';
+
+ $session = $this->getSession();
+ $page = $session->getPage();
+ $assert_session = $this->assertSession();
+
+ $this->doTestCreateMediaType($media_type_id, 'file');
+
+ // Hide the name field widget to test default name generation.
+ $this->hideMediaTypeFieldWidget('name', $media_type_id);
+
+ $test_filename = $this->randomMachineName() . '.txt';
+ $test_filepath = 'public://' . $test_filename;
+ file_put_contents($test_filepath, $this->randomMachineName());
+
+ // Create a media item.
+ $this->drupalGet("media/add/{$media_type_id}");
+ $page->attachFileToField("files[{$source_field_id}_0]", \Drupal::service('file_system')->realpath($test_filepath));
+ $result = $assert_session->waitForButton('Remove');
+ $this->assertNotEmpty($result);
+ $page->pressButton('Save');
+
+ $assert_session->addressEquals('media/1');
+
+ // Make sure the thumbnail is displayed.
+ $assert_session->elementAttributeContains('css', '.image-style-thumbnail', 'src', 'generic.png');
+
+ // Make sure checkbox changes the visibility of log message field.
+ $this->drupalGet("media/1/edit");
+ $page->uncheckField('revision');
+ $assert_session->elementAttributeContains('css', '.field--name-revision-log-message', 'style', 'display: none');
+ $page->checkField('revision');
+ $assert_session->elementAttributeNotContains('css', '.field--name-revision-log-message', 'style', 'display');
+
+ // Load the media and check if the label was properly populated.
+ $media = Media::load(1);
+ $this->assertEquals($test_filename, $media->getName());
+
+ // Test the MIME type icon.
+ $icon_base = \Drupal::config('media.settings')->get('icon_base_uri');
+ file_unmanaged_copy($icon_base . '/generic.png', $icon_base . '/text--plain.png');
+ $this->drupalGet("media/add/{$media_type_id}");
+ $page->attachFileToField("files[{$source_field_id}_0]", \Drupal::service('file_system')->realpath($test_filepath));
+ $result = $assert_session->waitForButton('Remove');
+ $this->assertNotEmpty($result);
+ $page->pressButton('Save');
+ $assert_session->elementAttributeContains('css', '.image-style-thumbnail', 'src', 'text--plain.png');
+ }
+
+}