CS 23 will expose you to many useful development tools. Some of these tools you will be expected to use throughout the semester, others will be required for only a few assignments.
You are responsible for the following in CS 23
My short list
JUnit, Testing Resources for Extreme Programming
JUnitTest Infected: Programmers Love Writing Tests - gives an example
Alternative descriptions
JUnit Testing Utility Tutorial by Ashley J.S Mills
cs2335_junit from Georgia Tech
Jester - Jester finds code that is not covered by your JUnit tests.
Other testing framework
CUnit - a testing framework that is being developed
Google Directory - Computers > Software > Build Management > Make Tools