fn check_positive(x: int) -> int {
    unless x > 0 {
        return -1;
    }
    return x * 2;
}

fn safe_access(ptr: int*) -> int {
    guard ptr != NULL else {
        return -999;
    }
    return *ptr;
}

test "test_guard_unless" {
    println "Testing guard and unless...";
    
    // Unless with true condition (should NOT enter block)
    let res1 = check_positive(10);
    if (res1 == 20) {
        println "  -> unless (pass condition): Passed";
    } else {
        println "  -> unless (pass condition): Failed";
        exit(1);
    }
    
    // Unless with false condition (should enter block)
    let res2 = check_positive(-5);
    if (res2 == -1) {
        println "  -> unless (fail condition): Passed";
    } else {
        println "  -> unless (fail condition): Failed";
        exit(1);
    }
    
    // Guard with valid pointer
    let val = 42;
    let p = &val;
    let res3 = safe_access(p);
    if (res3 == 42) {
        println "  -> guard (valid ptr): Passed";
    } else {
        println "  -> guard (valid ptr): Failed";
        exit(1);
    }
    
    // Guard with null pointer
    let res4 = safe_access(NULL);
    if (res4 == -999) {
        println "  -> guard (null ptr): Passed";
    } else {
        println "  -> guard (null ptr): Failed";
        exit(1);
    }
    
    println "All guard/unless tests passed!";
    
}