Adding tests and feedback

Author: karthick-murugan

features/user.feature

@@ -728,4 +728,12 @@ Feature: Manage WordPress users
       """
       newtestuser
       """
+  Scenario: Updating an invalid user should return an error
+    Given a WP install
+    When I try `wp user update 9999 --user_pass=securepassword`
+    Then the return code should be 1
+    And STDERR should contain:
+      """
+      Error: No valid users found.
+      """
 

src/User_Command.php

@@ -546,7 +546,7 @@ public function update( $args, $assoc_args ) {
 		}
 
 		if ( empty( $user_ids ) ) {
-			exit( 1 );
+			WP_CLI::error( 'No valid users found.' );
 		}
 
 		$skip_email = Utils\get_flag_value( $assoc_args, 'skip-email' );