I recently attended a lecture about developing shutdown software for a nuclear power plant. The development process involved three key stages: Formal Requirements Documents, a Software Design Document, and finally, Coding. Each step in the process is accompanied by formal verification processes and an audit which produces a Hazard Analysis Report. Code also goes through code review and verification.

I wonder if Intergraph employed a testing plan quite as thorough.

Development cycle diagram: http://i.imgur.com/RaBSNHN.png (from the below PDF, page 4)

The entire paper: http://procon.bg/system/files/28.18_Lawford_Wassyng.pdf