Where did you learn to unit test? How did you learn?

[John Ochiltree]

David Broadwell wrote:

>> I've noticed in my development that Python programmers (in general)
>> write more unit tests than their java counterparts.  If I download a
>> project off of jakarta.apache.org, it very rarely has unit tests.
>> However, when I download a python module, it frequently has unit
>> tests.
> 
> For the less educated here(spreading the bug early);  What exactly is a
> unit test? How does the investment payoff? Where can the newer programmers
> find good examples of unit tests?
> 
> ( I personally know the answer to some of these, but answers should be
> good for the group )

Kent Beck's Extreme Programming Explained
and Mark Pilgrim's Dive into Python http://diveintopython.org/