A CxxTest developer utilizes the CxxTest framework for unit testing in C++ projects. They design, write, and maintain test cases to verify the functionality and reliability of the code. They use the framework's features like test discovery, fixture setup/teardown, and exception handling to automate testing processes. They also utilize CxxTest to generate test suites in a portable way. They are involved in debugging, identifying software defects, and verifying fixes to ensure code quality. Additionally, they collaborate with the development team, communicating test results and working together to resolve any identified issues.