diff --git a/tests/phpunit/tests/admin/includesMedia.php b/tests/phpunit/tests/admin/includesMedia.php
new file mode 100644
index 0000000000000..4c90ed738b98f
--- /dev/null
+++ b/tests/phpunit/tests/admin/includesMedia.php
@@ -0,0 +1,91 @@
+<?php
+
+/**
+ * @group media
+ * @group admin
+ */
+class Tests_Admin_includesMedia extends WP_UnitTestCase {
+	/** @var \WP_Post */
+	protected static $post;
+	/** @var \WP_Post */
+	protected static $different_post;
+
+	public static function wpSetUpBeforeClass( \WP_UnitTest_Factory $factory ) {
+		self::$post           = $factory->post->create_and_get();
+		self::$different_post = $factory->post->create_and_get();
+	}
+
+	public static function wpTearDownAfterClass() {
+		wp_delete_post( self::$post->ID, true );
+		wp_delete_post( self::$different_post->ID, true );
+		self::$post           = null;
+		self::$different_post = null;
+	}
+
+	public function setUp() {
+		parent::setUp();
+
+		add_filter( 'pre_http_request', [ $this, 'internal_fake_download_url' ], 10, 3 );
+	}
+
+	public function tearDown() {
+		parent::tearDown();
+
+		$this->remove_added_uploads();
+		remove_filter( 'pre_http_request', [ $this, 'internal_fake_download_url' ] );
+	}
+
+	/**
+	 * Filters whether to preempt an HTTP request's return value. Mocking the
+	 * response. Since ticket 49631
+	 *
+	 * @param false  $preempt Whether to preempt an HTTP request's return value. Default false.
+	 * @param array  $parsed_args HTTP request arguments.
+	 * @param string $url The request URL.
+	 *
+	 * @return array
+	 */
+	public function internal_fake_download_url( $preempt, array $parsed_args, $url = '' ) {
+		// Just need an image content string to fill the new image, keeping the same mime type.
+		file_put_contents( $parsed_args['filename'], file_get_contents( DIR_TESTDATA . '/images/canola.jpg' ) );
+
+		return [
+			'response' => [
+				'code' => 200,
+			],
+		];
+	}
+
+	/**
+	 * @ticket 49631
+	 */
+	public function test_media_sideload_image() {
+		$year  = gmdate( 'Y' );
+		$month = gmdate( 'm' );
+
+		$image_source = 'http://' . WP_TESTS_DOMAIN . '/external/source/image1.jpg';
+		$image        = 'http://' . WP_TESTS_DOMAIN . "/wp-content/uploads/{$year}/{$month}/image1.jpg";
+		$image_html   = addslashes( $image );
+
+		$media_html = media_sideload_image( $image_source, self::$post->ID );
+
+		$this->assertNotWPError( $media_html );
+		$this->assertRegExp( "~<img src='$image_html' alt='' \/>~", $media_html );
+
+		$image_source = 'http://' . WP_TESTS_DOMAIN . '/external/source/image2.jpg';
+		$image        = 'http://' . WP_TESTS_DOMAIN . "/wp-content/uploads/{$year}/{$month}/image2.jpg";
+
+		$media_src = media_sideload_image( $image_source, self::$different_post->ID, null, 'src' );
+
+		$this->assertEquals( $image, $media_src );
+
+		$image_source = 'http://' . WP_TESTS_DOMAIN . '/external/source/image3.jpg';
+
+		$media_id                   = media_sideload_image( $image_source, self::$different_post->ID, null, 'id' );
+		$attachment_meta_source_url = get_post_meta( $media_id, '_source_url', true );
+
+		$this->assertInternalType( 'numeric', $media_id );
+		$this->assertEquals( $image_source, $attachment_meta_source_url );
+	}
+
+}