Index: src/wp-includes/update.php
===================================================================
--- src/wp-includes/update.php	(revision 28062)
+++ src/wp-includes/update.php	(working copy)
@@ -141,31 +141,47 @@
 			else
 				$offer[ $offer_key ] = esc_html( $value );
 		}
 		$offer = (object) array_intersect_key( $offer, array_fill_keys( array( 'response', 'download', 'locale',
 			'packages', 'current', 'version', 'php_version', 'mysql_version', 'new_bundled', 'partial_version', 'notify_email' ), '' ) );
 	}
 
 	$updates = new stdClass();
 	$updates->updates = $offers;
 	$updates->last_checked = time();
 	$updates->version_checked = $wp_version;
 
 	if ( isset( $body['translations'] ) )
 		$updates->translations = $body['translations'];
 
-	set_site_transient( 'update_core',  $updates);
+	set_site_transient( 'update_core', $updates );
+
+// Testing only, causes an update cron task to be run every 90seconds
+$body['ttl'] = 90;
+
+	if ( !empty( $body['ttl'] ) ) {
+		$ttl = (int) $body['ttl'];
+		if ( $ttl && ( time() + $ttl < wp_next_scheduled( 'wp_version_check' ) ) ) {
+			// Queue an event to re-run the update check in $ttl seconds
+			wp_schedule_single_event( time() + $ttl, 'wp_version_check' );
+		}
+	}
+
+	// Trigger a Background Updates check if running non-interactively, and we weren't called from the update handler
+	if ( defined( 'DOING_CRON' ) && DOING_CRON && ! doing_action( 'wp_maybe_auto_update' ) ) {
+		do_action( 'wp_maybe_auto_update' );
+	}
 }
 
 /**
  * Check plugin versions against the latest versions hosted on WordPress.org.
  *
  * The WordPress version, PHP version, and Locale is sent along with a list of
  * all plugins installed. Checks against the WordPress server at
  * api.wordpress.org. Will only check if WordPress isn't installing.
  *
  * @since 2.3.0
  * @uses $wp_version Used to notify the WordPress version.
  *
  * @param array $extra_stats Extra statistics to report to the WordPress.org API.
  * @return mixed Returns null if update is unsupported. Returns false if check is too soon.
  */