Articles like this one make me wonder what percent of the development community actually uses TDD. Shouldn't it be natural, even expected, to see the tests tha

Articles like this one make me wonder what percent of the development community actually uses TDD. Shouldn't it be natural, even expected, to see the tests that drove each iteration of abstraction? I am particularly interested in how one defines and implements tests for scaling and performance requirements like the 'Lazy Generation' example. Now the standard response will be that it's an article (or programming book, or interview question) so for the sake of brevity and clarity we omitted the test. Wouldn't well defined tests help shape the correct amount of generalization and abstraction?