We Don’t Need No Stinkin’ Code: Testing Software Requirements
Testing requirements can reveal errors long before the code is implemented. It’s cheaper, faster, and even kind of fun.
Someone once asked me when you can begin testing software. “As soon as you’ve written your first requirement, you can begin testing,” I replied. It’s hard to visualize how a system will function by reading some requirements. Tests that are based on requirements make the expected system behaviors more tangible. Even the simple act of designing tests reveals many requirements problems long before you can execute those tests on a running system.
Requirements and Tests
Tests and requirements present complementary views of the system. Creating multiple views of a system — written requirements, diagrams, tests, prototypes, and so forth — provides a much richer understanding of the system than can any single representation. Some agile development methods emphasize writing user acceptance tests from user stories in lieu of writing detailed functional requirements. Thinking about the system from a testing perspective is valuable, but that approach still leaves you with just a single representation of requirements knowledge, so you must trust it to be correct.
