In my head requirements only provide an overview, but don't dictate specific structure e.g. class/function structure. A majority of test suites require knowled

In my head requirements only provide an overview, but don't dictate specific structure e.g. class/function structure. A majority of test suites require knowledge of code structure (and thus to write the tests). To write the code before tests you either need to dictate some strict form of input/output, and test based on those only; OR, use a test suite that is very flexible. BDD seems to cheat by writing "tests" that aren't fully executable until you fill in the functional specifics later.