Cleanroom process model: a critical examination

Since Harlan Mills introduced it more than 20 years ago, the Cleanroom process model has enjoyed considerable-and unwarranted-favorable publicity. Almost nothing critical of Cleanroom has been published. Is it because Cleanroom is beyond reproach or because the best would-be critics have not taken Cleanroom seriously? Despite 20 plus years of passionate advocacy, Cleanroom has not become part of the software development mainstream. During this same period, other quality abetting practices have, including formal inspections, requirements analysis, configuration control, structured programming, systematic testing under coverage tools, and information hiding. But not Cleanroom. Cleanroom advocates many things with which the author agrees. There is, however, one fundamental tenet of the Cleanroom doctrine that moves him to criticism: its continuing attack on all forms of testing other than the specific stochastic testing it advocates. Cleanroom's attack on proper unit testing is especially onerous because it has promoted dangerous malpractice.