#include <stdio.h>
#include <assert.h>
#include <math.h>
#include "calculator.h"

void test_add() {
    assert(add(2, 3) == 5);
    assert(add(-1, 1) == 0);
    assert(add(0, 0) == 0);
    printf("test_add passed\n");
}

void test_subtract() {
    assert(subtract(5, 3) == 2);
    assert(subtract(1, 1) == 0);
    assert(subtract(0, 5) == -5);
    printf("test_subtract passed\n");
}

void test_multiply() {
    assert(multiply(3, 4) == 12);
    assert(multiply(0, 5) == 0);
    assert(multiply(-2, 3) == -6);
    printf("test_multiply passed\n");
}

void test_divide() {
    assert(fabs(divide(10, 2) - 5.0) < 0.001);
    assert(fabs(divide(7, 2) - 3.5) < 0.001);
    assert(divide(5, 0) == 0.0);
    printf("test_divide passed\n");
}

int main() {
    printf("Running calculator tests...\n\n");
    test_add();
    test_subtract();
    test_multiply();
    test_divide();
    printf("\nAll tests passed!\n");
    return 0;
}