Game Development Reference
Figure 12.2 NFL 2K5defensive tendencies for players Haiken and Danny.
On defense there are also differences between the two players, as shown in Figure 12.2.
Haiken will tap the A button to speed up the active defender about 95% of the time
while Danny taps A about 67% (two thirds) of the time on defense and holds down A
to charge about 33% of the time (one third). Danny also shows about an 80% prefer-
ence for Wrapping the ball carrier when tackling, where Haiken favors Wrapping only
60% of the time.
Why is it important to account for these tendencies? Testing based entirely on bal-
anced use of the game features would not reveal defects such as a memory overflow
caused by tapping the A button repeatedly on every play over the course of a maxi-
mum length game.
Even the VIP feature itself is not immune to usage bugs. In the VIP Viewer, Haiken's
Passing Chart shows 999/999 for Middle Medium pass completions/attempts. The
actual numbers of 1383 completions and 2278 attempts are properly shown in the
Statbook view. It seems the Passing Chart doesn't account for pass-happy players run-
ning up large numbers by playing five seasons of Franchise mode with some 60-
minute games thrown in.
It's possible to generate Cleanroom tests using any of the methods covered in this
book. You can also create your own Cleanroom tests on-the-fly. A usage probability
must be assigned to each step in the test. This can be done in writing or you can keep
track in your head. Use the usage probability to select test steps, values, or branches
and put them in sequence to produce tests that reflect your usages. For example, if you
expect a simulation game player to develop residential property 50% of the time,
commercial property 30% of the time, and industrial property 20% of the time, then
your Cleanroom tests will reflect those same frequencies.