Maximum prime difference

#[test]
fn t1() {
    let start = std::time::Instant::now();
    let val = Solution::maximum_prime_difference(vec![4, 2, 9, 5, 3]);
    let expected = 3;
    log_result!(val == expected, "t1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t2() {
    let start = std::time::Instant::now();
    let val = Solution::maximum_prime_difference(vec![4, 8, 2, 8]);
    let expected = 0;
    log_result!(val == expected, "t2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t3() {
    let start = std::time::Instant::now();
    let val = Solution::maximum_prime_difference(vec![7]);
    let expected = 0;
    log_result!(val == expected, "t3", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t4() {
    let start = std::time::Instant::now();
    let val = Solution::maximum_prime_difference(vec![2, 4, 6, 8, 11]);
    let expected = 4;
    log_result!(val == expected, "t4", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t5() {
    let start = std::time::Instant::now();
    let val = Solution::maximum_prime_difference(vec![2, 3, 5, 7, 11, 13]);
    let expected = 5;
    log_result!(val == expected, "t5", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t6() {
    let start = std::time::Instant::now();
    let val = Solution::maximum_prime_difference(vec![3, 4, 8, 9, 7]);
    let expected = 4;
    log_result!(val == expected, "t6", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t7() {
    let start = std::time::Instant::now();
    let val = Solution::maximum_prime_difference(vec![2, 4, 6, 97, 100]);
    let expected = 3;
    log_result!(val == expected, "t7", start, &expected, &val);
    assert_eq!(val, expected);
}