The structured walk-through test occurs when the functional representatives meet to review the plan in detail. This involves a thorough look at each of the plan steps, and the procedures that are invoked at that point in the plan. This ensures that the actual planned activities are accurately described in the plan. The checklist test is a method of testing the plan by distributing copies to each of the functional areas. The simulation test plays out different scenarios. The parallel test is essentially an operational test that is performed without interrupting current processing.
Source: HARE, Chris, CISSP Study Guide: Business Continuity Planning Domain,