test_comparer.c

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

typedef int (*Comparer)(void*, void*);
typedef int (*Generator)(void*);

int test1(Comparer comparer, void *obj1, void *obj2) {
	int res1, res2;

	res1 = comparer(obj1, obj2);
	res2 = comparer(obj2, obj1);
	if(res1 < 0) {
		return res2 > 0;
	}
	if(res1 == 0) {
		return res2 == 0;
	}
	if(res1 > 0) {
		return res2 < 0;
	}
}

int test2(Comparer comparer, void *obj1, void *obj2, void *obj3) {
	int res1, res2, res3;

	res1 = comparer(obj1, obj2);
	res2 = comparer(obj2, obj3);
	res3 = comparer(obj3, obj1);
	int allUp = res1 >= 0 && res2 >= 0 && res3 >= 0;
	int allDown = res1 <= 0 && res2 <= 0 && res3 <= 0;
	return !((res1 || res2 || res3) && (allUp || allDown));
}

int test_comparable(Comparer comparer, Generator generator, size_t size, int tries) {
	int i;
	void *obj1, *obj2, *obj3;

	obj1 = malloc(size);
	obj2 = malloc(size);
	obj3 = malloc(size);

	for(i = 0; i < tries; i++) {
		generator(obj1);
		generator(obj2);
		generator(obj3);

		if(!(test1(comparer, obj1, obj2) && test1(comparer, obj2, obj3) && test1(comparer, obj3, obj1) && test2(comparer, obj1, obj2, obj3))) {
			return 0;
		}
	}
	return 1;
}




int my_comparer(void *pt1, void *pt2) {
	int n1, n2;

	n1 = *((int*)pt1);
	n2 = *((int*)pt2);
	if(n1 < n2) {
		return -1;
	}
	if(n1 == n2) {
		return 0;
	}
	return 1;
}

int my_generator(void *pt) {
	static int initialized = 0;
	if(!initialized) {
		srand(time(NULL) | rand());
		initialized = 1;
	}
	*((int*)pt) = rand();
}

int main() {
	if(test_comparable(my_comparer, my_generator, sizeof(int), 1000)) {
		printf("Success!\n");
	} else {
		printf("Fail!\n");
	}
	return 0;
}