unit testing
	unit = method
	write main (stub) explicitly to test (call) the method

get values for testing
	random generation
	loop to generate
	literals for special cases
	user input (files to retest (regression testing), redirection of input)

special cases: valid values (positive test), invalid values (negative test),
	boundary cases 

white-box testing: see function, test every branch
black-box testing: blind test, try to break code

evaluating output
	- look & evaluate
	- calculate by hand (calculator)
	- compare result to another known method for 
			computing value = oracle
	- do problem backwards/inverse operation


FINDING & FIXING ERRORS IN PROGRAM

- software/application debuggers
	- run until checkpoint
	- inspect variable
	- step through line by line
	- step over

- in-code debugging tricks
	- print statements to see variable values
	- new Throwable().printStackTrace()
	- throw new IllegalArgumentException()


public class Check
{
	public static void assert(boolean condition)
	{
		if (!condition)
		{	new Throwable().printStackTrace();
//			throw new IllegalArgumentException();
			System.exit(1);
		}
	}
}

public class blah
{

public static void main ...
{
	Check.assert(denominator != 0);

}
}