A Little Treatise on the Nature of Software

• A piece of code can be anywhere between engineering and craft
• Engineers have comprehensive testing suites to cover rigorously detailed requirements and conditions
• Craftsmen don't test at all - they try it out
• Software requirements can only be defined in terms of input-output...
• ...and when used in complex manner it is very hard to predict/cover all possible situations
• Smaller the unit is, more comprehensive test can be designed
• It can be very hard to provide an adequate testing environment for the small units