Check if word equals summation of two words

#[test]
fn t1() {
    let start = std::time::Instant::now();
    let val = Solution::is_sum_equal("acb".to_string(), "cba".to_string(), "cdb".to_string());
    let expected = true;
    log_result!(val == expected, "t1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t2() {
    let start = std::time::Instant::now();
    let val = Solution::is_sum_equal("aaa".to_string(), "a".to_string(), "aab".to_string());
    let expected = false;
    log_result!(val == expected, "t2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t3() {
    let start = std::time::Instant::now();
    let val = Solution::is_sum_equal("aaa".to_string(), "a".to_string(), "aaaa".to_string());
    let expected = true;
    log_result!(val == expected, "t3", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t4() {
    let start = std::time::Instant::now();
    let val = Solution::is_sum_equal("a".to_string(), "b".to_string(), "b".to_string());
    let expected = true;
    log_result!(val == expected, "t4", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t5() {
    let start = std::time::Instant::now();
    let val = Solution::is_sum_equal("j".to_string(), "j".to_string(), "b".to_string());
    let expected = false;
    log_result!(val == expected, "t5", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t6() {
    let start = std::time::Instant::now();
    let val = Solution::is_sum_equal("ba".to_string(), "a".to_string(), "ba".to_string());
    let expected = true;
    log_result!(val == expected, "t6", start, &expected, &val);
    assert_eq!(val, expected);
}