I can give you some pointers.
1) A good discussion about Unit Testing on Hacker News. Is most unit testing a waste or not? https://news.ycombinator.com/item?id=7353767
2) A story about unit testing at Airbnb: http://nerds.airbnb.com/testing-at-airbnb/
3) Practical tips for test driven development: http://soundsoftware.ac.uk/unit-testing-why-bother/