simple example of using assert for tdd in c

ex_tdd_assert.c

#include <stdio.h>
#include <assert.h>

#define DEBUG(res) printf("\n%s in '%s' on function %s() line %d, tests_run: %d, tests_ok: %d, tests_fail: %d\n", \
		res ? "success" : "fail", __FILE__, __func__, __LINE__, tests_run, tests_ok, (tests_run-tests_ok))
#define _assert(test) do { if (!(test)) { DEBUG(test); tests_run++; return 1; } \
	DEBUG(test); tests_run++; tests_ok++; } while(0)

int tests_ok = 0;
int tests_run = 0;

struct tmp {
	int x;
};

struct tmp lp;

struct tmp *letsgo(struct tmp *lu)
{
	return lu;
}

static int letsgo_test(void)
{
	struct tmp *la = NULL;
	_assert(letsgo(la) != NULL);
	return 0;
}

int power(int x) {
	_assert(x != 3);
	return x * x;
}

int all_tests() {
	int res = 0, x = 1;

	letsgo_test();

	for (; x < 6; x++) {
		_assert(power(x) != 25);
	}

	return 0;
}

int main(int argc, char **argv) {
	int result = all_tests();

	if (result == 0)
		printf("Result: PASSED\n");
	else
		printf("Result: FAIL\n");

	printf("Tests run: %d, Tests OK: %d, Tests FAIL: %d\n", 
		tests_run, tests_ok, (tests_run-tests_ok));

	return result != 0;
}