Cleanup for 2022 day 1: Turned into a lib and introduced parse errors instead of silently defaulting to 0

2022/day01-calorie_counting/src/lib.rs

@@ -0,0 +1,41 @@
+use std::num::ParseIntError;
+
+fn try_parse_cal_list(list: &str) -> Result<Vec<usize>, ParseIntError> {
+    let mut cals: Vec<_> = list.split("\n\n")
+        .collect::<Vec<&str>>()
+        .iter()
+        .map(|individual_list| individual_list.lines()
+             .map(|n| n.parse::<usize>())
+             .sum::<Result<usize, _>>())
+        .collect::<Result<Vec<_>, _>>()?;
+
+    cals.sort_by_key(|i| std::cmp::Reverse(*i));
+    Ok(cals)
+}
+
+pub fn run(input: &str) -> Result<(usize, usize), ParseIntError> {
+    let elves = try_parse_cal_list(input)?;
+    Ok((elves[0], elves.iter().take(3).sum::<usize>()))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn read_file(path: &str) -> String {
+        std::fs::read_to_string(path)
+            .expect("File not Found")
+    }
+
+    #[test]
+    fn sample_input() {
+        let list = read_file("tests/sample_input");
+        assert_eq!(run(&list), Ok((24000, 45000)));
+    }
+
+    #[test]
+    fn challenge_input() {
+        let list = read_file("tests/input");
+        assert_eq!(run(&list), Ok((71780, 212489)));
+    }
+}

2022/day01-calorie_counting/src/main.rs

@@ -1,47 +0,0 @@
-use std::fs;
-
-fn parse_cal_list(list: String) -> Vec<u32> {
-    let mut cals: Vec<u32> = list.split("\n\n")
-        .collect::<Vec<&str>>()
-        .iter()
-        .map(|individual_list| individual_list.lines()
-             .map(|n| n.parse::<u32>().unwrap_or(0))
-             .sum::<u32>())
-        .collect();
-
-    cals.sort();
-    cals.reverse();
-    cals
-}
-
-fn main() {
-    let list = read_file("input");
-
-    let elves = parse_cal_list(list);
-
-    println!("Max: {}", elves[0]);
-    println!("Top 3: {}", elves.iter().take(3).sum::<u32>())
-}
-
-fn read_file(path: &str) -> String {
-    fs::read_to_string(path)
-        .expect("File not Found")
-}
-
-#[test]
-fn sample_input() {
-    let list = read_file("tests/sample_input");
-    let elves = parse_cal_list(list);
-
-    assert_eq!(elves[0], 24000);
-    assert_eq!(elves.iter().take(3).sum::<u32>(), 45000);
-}
-
-#[test]
-fn challenge_input() {
-    let list = read_file("tests/input");
-    let elves = parse_cal_list(list);
-
-    assert_eq!(elves[0], 71780);
-    assert_eq!(elves.iter().take(3).sum::<u32>(), 212489);
-}