yearly.rs

fn main() {
    println!("Hello, world!");
}

fn process(input: &str) -> Vec<Vec<String>> {
    input.split("\n")
        .map(|line| line.split(','))
        .map(|fields| fields.map(|field| field.to_string()))
        .map(|fields| fields.collect::<Vec<_>>())
        .collect::<Vec<_>>()
}

fn total_by_category(transactions: [Transaction]) -> [()] {
}

#[cfg(test)]
mod business_rules {
    use crate::total_by_category;

    #[test]
    fn sum_by_category() {
        assert_eq!([()], total_by_category([]));
    }
}

#[cfg(test)]
mod parse_csv {
    use crate::process;

    #[test]
    fn read_in_one_line() {
        let input= "1,2,3";
        let strings= process(input);
        assert_eq!("1", strings[0][0]);
        assert_eq!("2", strings[0][1]);
        assert_eq!("3", strings[0][2]);
    }

    #[test]
    fn read_in_all_lines() {
        let input= "1,2,3\n4,5,6";
        let strings = process(input);
        assert_eq!("1", strings[0][0]);
        assert_eq!("2", strings[0][1]);
        assert_eq!("3", strings[0][2]);
        assert_eq!("4", strings[1][0]);
        assert_eq!("5", strings[1][1]);
        assert_eq!("6", strings[1][2]);
    }
}