1.4. What You Can Test: Schedule, Resources, and Budget
Whether I've used an informal approach or the more formal FMEA technique, I now have a prioritized outline of quality risks. This is analogo us to the requirements for the overall project; the list of critical quality risks documents the essential requirements for my test effort. Now, I need to figure out a test schedule and a budget that will allow me to test the scariest risks.
One of my first managers was fond of this saying: "Schedule, cost, and quality—pick two." This pithy remark means that while for a given feature set you can freely select any two of these variables, doing so determines the third variable. I call this rule, which is illustrated in Figure 1.7, the "Iron Box and Triangle" of system development. The clockwise arrow indicates refinement during the planning stage. These refinements balance features, schedule, cost, and quality. Once implementation begin s, the feature set becomes more rigid, the schedule more painful to change, and the budget increases less likely. Within the fixed "box" enclosing the feature set in Figure 1.7, the two lines that are drawn to select the schedule and the cost determine the placement of the third line (quality) that completes the triangle.
This creates a planning conundrum in that you have only a rough idea of what your test project is about, but the window of opportunity that might allow a realistic schedule and an adequate budget is closing. (And even this scenario assumes ...