How to spy on static data in C modules?

Question

Suppose that I have a module which has some static data, If I want to spy on these values using a test file, Is there an elegant way to do that without using getters?

Take a look at [How to test a static function?](https://stackoverflow.com/a/593423/15168). The basic solution works for variables too. I note that the `ModuleArray` in the diagram is not 'static data' in the sense of 'qualified with the keyword `static`' so it is visible outside the module — even if there isn't (yet) a header that declares it. Of course, that could simply be a bug — the variable should be qualified with `static` unless there is a need to access it outside the module, and if it should be accessed, then there should be a header that declares it. — Jonathan Leffler, Feb 14 '20 at 15:47

score 1 · Answer 1 · answered Feb 14 '20 at 15:41

Unit testing is one of the rare times it makes sense to directly include a .c file. That will give you access to static functions and variables inside the module.

For example:

#include <string.h>
#include <assert.h>

#include "file_to_test.c"

int main()
{
    Module_Init();
    assert(strcmp(ModuleArray, "string_to_test") == 0);
}

How to spy on static data in C modules?

1 Answers1