I can see it working if you have very few developers touching each piece of code, or if you get to exert control over the final application. But I don't see how it can work for large codebases or teams over long periods of time (read: large businesses)... especially not for library development, where your team is only responsible for providing library functionality (like string.indexOf(string) in my example, or matrix multiplication, or regexes, or whatever libraries do) and you don't necessarily even know whom the users are. There is no "system" or "integration" at that point, you're just developing one layer of code there, which is the library -- a piece of code responsible for doing just one thing. How the heck do you make sure arbitrary team members touching code don't end up introducing silly bugs over time, if not with unit tests?
Have you built any commercial libraries in this manner, rather than applications? i.e. where everyone on your team is jointly responsible for your library's development (like the implementation of string.indexOf(string) in my example), and other folks (whether inside or outside the company) are the ones who piece together the libraries to create their final application(s)?
