I'll second the TUT (Template Unit Test) framework; it's super lightweight and extremely flexible, not to mention really easy to setup and use out of the box (a single header include, a little bit of main/setup code, and 24 lines of test code later you have a unit test). I've combined it with binfmtc (run C++ programs as scripts) for rapid prototyping/TDD/learning templates to great success, including embedded software development. Due to it being able to output to XML, it also dovetailed in nicely with Jenkins (CI) and Sonar on successive projects of mine.