Art of Unit Testing

[Jesse W]

Dear kindly snake people,
	I have read about, and downloaded, some of the Python unit 
testing frameworks available, but I have never yet been able to 
actually use any one of them to implement actual _tests_. I wish to 
use unit tests(at least, the kind of unit tests used in Extreme 
Programming(I think))because one of the claims of aficionados of 
this approach is that it helps them get over the problem of how to 
make programs that can't be kept in mind as a whole. This amazing 
feat is done, say the aficionados, by writing the unit tests out before 
the code.  I have both great hope and significant doubts about this 
method.
	I hope, as I said above, that this method will allow me to finish 
various projects I have started and had to abandon because I got 
stuck in binds I could not specifically understand or find out how to 
resolve.  My doubts lie with the thought that it is very difficult to 
figure out what the requirements of a program will be before you 
write the program, and will this method make programming into a 
tiresome, irritating task, even if I can write these bigger programs?
	My question to you all is this:  Do you have any suggestions on 
how to deal with learning to use unit testing in this way, or examples 
of setting up games with this kind of unit testing, or GUI programs?  
Really, any thoughts or comments you might have about this form of 
unit testing, or how to learn to use it, would be very appreciated.

				Thank you all for your time,
					Jesse F. Weinstein