error C2003: expected 'defined id' - c

Question

I made a mechanism for compiling only selected tests from a sequence of tests by defining the macros:
#define SELECTION(x) ((!defined (RUN_SELECTED_TESTS_ONLY)) || (defined (x)))
#define RUN_SELECTED_TESTS_ONLY
#define TEST_1 //Lets say I want only test1 to be compiled
#if SELECTION(TEST_1) //The line I'm getting the error on.
//code of test 1
#endif
#if SELECTION(TEST_2)
//code of test 2
#endif
While compilation I'm getting the error :
error C2003: expected 'defined id'
I'm getting the error only when TEST_1 or TEST_2 (or both) are defined.

Answer 1

An alternative definition for SELECTION:
#ifdef RUN_SELECTED_TESTS_ONLY
#define SELECTION defined
#else
#define SELECTION(x) 1
#endif
Notes:
Must be defined after RUN_SELECTED_TESTS_ONLY is.
Only works in GNU cpp and other preprocessors similarly permissive about operator defined being the result of a macro expansion.
Example:
#define RUN_SELECTED_TESTS_ONLY
#ifdef RUN_SELECTED_TESTS_ONLY
#define SELECTION defined
#else
#define SELECTION(x) 1
#endif
#define TEST_1
//#define TEST_2
#include <stdio.h>
int main()
{
#if SELECTION(TEST_1)
printf("Test 1\n");
#endif
#if SELECTION(TEST_2)
printf("Test 2\n");
#endif
return 0;
}
Output:
Test 1

Answer 2

What you have invokes undefined behaviour. C standard says that the defined preprocessor operator may not appear as a result of replacement.
C11 draft, 6.10.1 Conditional inclusion
4 Prior to evaluation, macro invocations in the list of preprocessing
tokens that will become the controlling constant expression are
replaced (except for those macro names modified by the defined unary
operator), just as in normal text. If the token defined is generated
as a result of this replacement process or use of the defined unary
operator does not match one of the two specified forms prior to macro
replacement, the behavior is undefined. After all replacements due to
macro expansion and the defined unary operator have been performed,
all remaining identifiers (including those lexically identical to
keywords) are replaced with the pp-number 0, and then each
preprocessing token is converted into a token.
If you can't perform same check at run-time, you could do:
#define RUN_SELECTED_TESTS_ONLY
#define TEST_1
#if ((!defined (RUN_SELECTED_TESTS_ONLY)) || (defined (TEST_1)))
//code of test 1
#endif
Basically performing the "selection" yourself.

Answer 3

The error you get means: An identifier must follow the preprocessor keyword. (from MSDN).
It doesn't work because you cannot you defined() 2 times in your macro SELECTION(x).
What you can do instead is something like:
#define SELECTION(x) (!RUN_SELECTED_TESTS_ONLY || x)
#define RUN_SELECTED_TESTS_ONLY 1
#define TEST_1 1
#define TEST_2 0
#if SELECTION(TEST_1)
//some code
#endif
int main() {
printf("%d\n", SELECTION(TEST_1));
printf("%d\n", SELECTION(TEST_2));
return 0;
}