I plan to introduce a set of standards for writing unit tests into my team. But what to include?
These two posts (Unit test naming best practices and Best practices for
Another item you can put in your standards is to try and keep your unit test size small. That is the actuall test methods themselves. Unless you are doing a full integration unit test there usually is no need for large unit tests, like say more than 100 lines. I'll give you that much in case you have a lot of setup to get to your one test. However if you do you should maybe refactor it.
People also talk about refactoring there code make sure people realize that unit tests is code too. So refactor, refactor, refactor.
I find the biggest problem in the uses I have seen is that people do not tend to recognize that you want to keep your unit tests light and agile. You don't want a monolithic beast for your tests after all. With that in mind if you have a method you are trying to test you should not test every possible path in one unit test. You should have multiple unit tests to account for every possible path through the method.
Yes if you are doing your unit tests correctly you should on average have more lines of unit test code than your application. While this sounds like a lot of work it will save you alot of time in the end when comes time for the inevitable business requirement change.