CUnit is a lightweight system for writing, administering, and running
unit tests in C. It provides C programmers a basic testing functionality
with a flexible variety of user interfaces. CUnit is built as a static
library which is linked with the user's testing code. It uses a simple
framework for building test structures, and provides a rich set of
assertions for testing common data types. In addition, several different
interfaces are provided for running tests and reporting results.

WWW: http://cunit.sourceforge.net/