nesting preprocessor directives or other trickery to conditionally redefine the static keyword

I am using unity for unit testing.

I have a header throughout my project that I include with some helper macros, like an assert wrapper that I can use to track which assert fired.

In that header I also have the following definition:

#define static //nothing

I learned that little trick from this article: http://ift.tt/1Orj0Pl

This allows me to write unit tests for static functions and it allows me to access any relevant file scope data from my test harness.

The trouble is this totally breaks static at the function scope. The article goes on to say if I do this:

#define static extern

Then any variable that is static at the function scope can then be defined within the test harness. We're off to the races, right? Not exactly.

Because the following occurs

void foo()
{
    extern bool my_flag = false;
}

Now we are supplying an initializer to declaration, which is invalid. So that means any static variable I handled this way would inherently need to be initialized after startup.

Because static variables within functions are relatively uncommon, I thought I might circumvent this by defining a new symbol, LOCAL_STATIC. So now in my header I have the following

#define static extern
#define LOCAL_STATIC static

But that does not work because those directives are evaluated strictly in order - #define LOCAL_STATIC static becomes #define LOCAL_STATIC extern, or at least that is what seems to be happening. Because LOCAL_STATIC produces the same error and indeed ends up getting changed to extern by the preprocessor.

So is there any way around this?

AFAIK anything like this is impossible:

#define LOCAL_STATIC  \
#undef static         \
static                \
#define static extern

The only thing I can think of is to leave static alone and define a new symbol, something like HARNESS_ACCESSIBLE. #ifdef UNIT_TEST #define HARNESS_ACCESSIBLE extern #else #define HARNESS_ACCESSIBLE static #endif

But that is going to clutter up the production code with this new weird thing "HARNESS_ACCESSIBLE". Static variables within functions are generally rare, but almost all static functions (except trivial helper functions) will need to be externally accessible by my test runner.

I've been trying to avoid writing a separate script that has to run before builds, but I am getting to that point now.