Embodiments of the present invention disclose a method, computer program product, and system for testing objects in a client-server environment. A server computing system receives at least one modification to a set of objects. The server computing system registers the at least one modification with a user identifier. The server computing system receives instructions to execute the set of objects with the at least one modification that is registered to the user identifier. The server computing system determines which of the set objects the at least one modification alters. The server computing system executes the set of objects, wherein the set of objects incorporates the at least one modification associated with the user identifier.