This comment feels orthogonal to TFA (but it makes a great strawman). The author was using rails apps as an example of how to think about testing and design, no

This comment feels orthogonal to TFA (but it makes a great strawman). The author was using rails apps as an example of how to think about testing and design, not laying out the one true path to software development. Whether it is a rails web app or a functional high frequency trading app, the author's point stands: don't let dogma dictate your testing strategy at the expense of harder to read, nastier to maintain code.