use std::fs;

pub fn add() -> Result<(), std::io::Error> {
    fs::write(
        "adunare.out",
        fs::read_to_string("./adunare.in")
            .expect("File could not be read!")
            .lines()
            .map(|s| s.parse::<isize>().unwrap_or(0))
            .sum::<isize>()
            .to_string(),
    )
}

#[cfg(test)]
mod tests {
    use super::add;
    use std::fs;

    #[test]
    fn test_add() {
        add();
        assert_eq!(fs::read_to_string("adunare.out").unwrap(), "376")
    }
}