I am new to test-driven development, but I'm loving it. There is, however, a main problem that prevents me from using it effectively.

I work for embedded medical applications, plain C, with safety issues.

Suppose you have module A that has a function A_function() that I want to test. This function call a function B_function, implemented in module B. I want to decouple the module so, as James Grenning teaches, I create a Mock module B that implements a mock version of B_function.

However the day comes when I have to implement module B with the real version of B_function. Of course the two B_function can not live in the same executable, so I don't know how to have a unique "launcher" to test both modules.

James Grenning way out is to replace, in module A, the call to B_function with a function pointer that can have the value of the mock or the real function according to the need. However I work in a team, and I can not justify this decision that would make no sense if it were not for the test, and no one asked me explicitly to use test-driven approach.

Maybe the only way out is to generate different a executable for each module.

Any smarter solution? Thank you