1. In a multi-tasking computer system, a method for isolating a first software task from other software tasks, comprising the steps of: rerouting a message from the first software task that is intended for one of the other software tasks to an external user operable to emulate the one other software task wherein, rerouting comprises: requesting that a test task interact with a common communications mechanism; and substituting a second set of routing information for a first set of routing information; and emulating the one other software task and generating a response message.