1. A messaging system, comprising: a broker cluster including a plurality of brokers configured to relay messages from at least one publisher to at least one subscriber over one or more networked cluster connections in accordance with a predefined publish/subscribe model related policy; a test driver configured to receive instructions regarding errors to be simulated in association with one or more components in the messaging system; a simulator configured to simulate a network link and properties associated with the link; and processing resources including at least one processor and a memory configured to: coordinate with the test driver and the simulator to selectively generate errors in one or more components of the messaging system, post-deployment and while it is live, in accordance with the instructions, and determine whether the messaging system appropriately handled the errors selectively generated in response to the instructions, wherein errors that are simulatable in association with one or more components in the messaging system include a partial subset of brokers in the broker cluster going offline, the entire broker cluster going offline, a disconnect between some or all broker connections to the at least subscriber, a broker start/stop event, and the at least one subscriber going offline.