Hello,

In my team of real-time-embedded C/C++ developers, most people don't have any culture of testing their code beyond the casual manual sanity checks. I personally strongly believe in advantages of autonomous automatic tests, but when I try to convince I get some reappearing arguments like:

1. We will spend more time on writing the tests than writing the code.
2. It takes a lot of effort to maintain the tests.
3. Our code is spaghetti; no way we can unit-test it.
4. Our requirement are not sealed – we’ll have to rewrite all the tests every time the requirements are changed.

Now, I'd gladly hear any convincing tips and advises, but what I am really looking for are references to researches, articles, books or serious surveys that show (preferably in numbers) how testing is worth the effort. Something like "We in IBM/Microsoft/Google, surveying 3475 active projects, found out that putting 50% more development time into testing decreased by 75% the time spent on fixing bugs" or "after half a year, the time needed to write code with test was only marginally longer than what used to take without tests".

Any ideas?

P.S.: I'm adding C++ tag too in case someone has a specific experience with convincing this, usually elitist, type of developers :-)