Faked Function Framework

In that case, perhaps you need to look at Mike Long‘s faked-function-framework (FFF) as suggested by James Grenning at this year’s BITsCon software conference.

Example

Say, you want to stub a method with the signature:

void calculateBigThing(int seed);

Using FFF you can do it like this:

/* Preamble */ 
#include "fff.h" 
DEFINE_FFF_GLOBALS; 

FAKE_VOID_FUNC1(calculateBigThing, int);

The statement above simply means fake (or stub, ignoring the cry of puritans) calculateBigThing as a function returning void, taking one int parameter.

Behind the scenes (using macros) FFF implements not only the stub, but also a mock like framework that makes it possible for you to write statements setting up expectations like this:

calculateBigThing_fake.return_val = 33;
ASSERT_EQUAL(expected, calculateBigThing_fake.arg0_history[0]);

ASSERT_EQUAL being your favorite xUnit (C/C++) testing framework assertion macro (CppUnit, CUnit, CppUTest, …).

You can also stub functions returning a value with up to 10 args and even set up sequences of return values.

References

Check out the work of Mike Long on https://github.com/meekrosoft/fff.

Also check out James Grenning articles on how to apply FFF dealing with low-level OS stuff.

And while you’re at it, read Mike Long’s excellent article on how to unit test operations on low level memory mapped variables using FFF.