How to design stub code that behaves differently for each test case

When running the test after adding the stub to the test, the execution result can be different for each test case.
The following is an example of stub code in which the result returned by the stub is written differently for each test case.

int result = 0;
if(CS_TESTCASENO() == 1) { // Modified to allow different behavior for each test case
	result = some_function1();
} else if(CS_TESTCASENO() == 2) {
        result = some_function2();
}
return result;