Yes, you can use the Eclipse debugger if you incorporate some test apps into your project (you can always pull them out to release/publish).
The way I got it all pulled together is that I add new test executables (just C++ mains) to the project and manually added them to the cmake files in the <project>/lib directory. Then I set the debugger to run whichever test executable I wanted. Inside there I could instantiate my new classes and call whatever functions I want (such as work() or a modified work() just for testing purposes). For test data I would either use a real signal saved with a file sink in GNURadio and just read it in, or create a function in my test program to generate it. Then I could step through my modules with the debugger. I'm personally a big fan of debuggers. Trying to debug with print statements to me is too painful/slow from a development process perspective.