Fix output message for STDIN input (#151)

Fix output message for STDIN input

Author: schlessera

features/db-import.feature

@@ -12,6 +12,15 @@ Feature: Import a WordPress database
       Success: Imported from 'wp_cli_test.sql'.
       """
 
+  Scenario: Import from STDIN
+    Given a WP install
+
+    When I run `wp db import -`
+    Then STDOUT should be:
+      """
+      Success: Imported from 'STDIN'.
+      """
+
   Scenario: Import from database name path by default and skip speed optimization
     Given a WP install
 

src/DB_Command.php

@@ -580,6 +580,8 @@ public function import( $args, $assoc_args ) {
 				: 'SET autocommit = 0; SET unique_checks = 0; SET foreign_key_checks = 0; SOURCE %s; COMMIT;';
 
 			$mysql_args['execute'] = sprintf( $query, $result_file );
+		} else {
+			$result_file = 'STDIN';
 		}
 		// Check if any mysql option pass.
 		$mysql_args = array_merge( $mysql_args, self::get_mysql_args( $assoc_args ) );