How the mocking works¶
The macro CESTER_MOCK_FUNCTION declares a weak reference of the function to mock, declares a __real_ function signature and at the last expansion stage declares and initialize a __weak_ wrapper function.
The following example mock a function
CESTER_MOCK_FUNCTION(power_of(int* num1, int num2), int,
int return_val = *num1;
while (num2-->1) {
return_val *= *num1;
}
return return_val;
)
First macro expansion we have
__attribute__((weak)) int power_of(int* num1, int num2);
extern int __real_power_of(int* num1, int num2);
In the final expansion
int __real_power_of(int* num1, int num2) {
int return_val = *num1;
while (num2-->1) {
return_val *= *num1;
}
return return_val;
}
At the end of the macro expansion we have
__attribute__((weak)) int power_of(int* num1, int num2);
extern int __real_power_of(int* num1, int num2);
int __real_power_of(int* num1, int num2) {
int return_val = *num1;
while (num2-->1) {
return_val *= *num1;
}
return return_val;
}
The function power_of will then be mocked if compiled with the -Wl,–wrap=power_of option.
The same logic applies to CESTER_MOCK_SIMPLE_FUNCTION macro except it returns the last parameter.