That reply reads disparaging, perhaps implying that the author needs to spend more time designing. But that's not necessarily true! Have you ever changed your c

That reply reads disparaging, perhaps implying that the author needs to spend more time designing. But that's not necessarily true! Have you ever changed your code to work around a bug in some version of a web browser, or compiler? If so, you discovered a limitation of TDD as it relates to components outside your control. Saying that "no methodology can solve this" is defeatist: there are lots of things you can do. One technique is to write your tests to use the actual component, instead of mocks. For example, I never mock the filesystem: I always design tests to run using the real thing. This reduces the chances that I've encoded some bogus assumption into my tests, and makes it more likely that I'll encounter the individual quirks of the filesystem.