I'm responsible for 50k+ lines of Java code in the Freenet project.
I can write unit tests for your Java stuff.
Ideally you would just give me the interface specifications of your code and let me write the unit tests without actually knowing the implementing code.
- It's much better if a person writes unit tests who doesn't know the code which is under test as it prevents mistakes from false assumptions about the code which someone might have who wrote the code himself.
(Of course I can also write unit tests directly from undocumented code if you just want to ensure that the code does not break in the future, consider this as very bad programming practice though. I'm offering this as well because undocumented code is something which happens rather often in the wilderness
I'd say 1 BTC/hour is a very fair starting price for you to evaluate how fast I am to write your tests.