By pg in On Lisp: >> It’s a long-standing principle of programming style that the functional elements of a program should not be too large. If some component of a program grows beyond the stage where it’s readily comprehensible, it becomes a mass of complexity which conceals errors as easily as a big city conceals fugitives. Such software will be hard to read, hard to test, and hard to debug. >>>

One of the problem is not treating tests also as a design problem as in what to test and what the code for tests should be like? I never see the rule of simplicity applied to the test code as well. Eventually it all becomes like a big city that conceal fugitive bugs.

EDIT: to end the quotation from pg book.