Some basic CYA I can see:

1) Ensure there is sufficient functional and technical design documentation against which the routines can be tested.

2) (updated) Make sure there is a sufficiently detailed project plan to include tasks for: systems analysis, functional and technical design, test planning, test script writing (e.g. using Expect), developing, unit-, integrated and functional testing, rework and implementation, to include a GANTT chart of the work done so far and by who to what % of completion, to avoid getting the blame for not meeting poorly conceived targets over which you had no control.

In response to formal testing against the plan, I find it a useful aid to bug-fixing to monitor execution with perl -d, setting breakpoints and examining variables to hunt down which line of code causes each failure.