Software Testing encompasses about different types of testing such as functional testing, unit testing (specific sections of code), blackbox testing, (external perspective of test object), glassbox testing (testing with an internal perspective of the system) and regression testing (ensuring that newly added features does not cause problems). In software testing, use cases, test cases and master test plans interact with each other. More elaborate testing includes integration testing (software modules tested as a group), system testing (detect faults within the system) and system integration testing (testing of systems coexistence with others).

Wikipedia
http://en.wikipedia.org/wiki/Software_testing