Cleanup for 2022 day 6: Turned into a lib and introduced Options instead of panicing

2022/day06-turning_trouble/src/lib.rs

@@ -0,0 +1,41 @@
+fn find_start_marker(message: &Vec<char>, distinct_character_count: usize) -> Option<usize> {
+    'char_iterator: for index in distinct_character_count-1..message.len() {
+        let mut found: Vec<char> = Vec::with_capacity(distinct_character_count);
+        for offset in 0..distinct_character_count {
+            let this_char = message[index+offset+1-distinct_character_count];
+            if found.contains(&this_char) { continue 'char_iterator; }
+            found.push(this_char);
+        }
+        return Some(index+1);
+    }
+    None
+}
+
+pub fn run(input: &str) -> (Option<usize>, Option<usize>) {
+    let chars = input.chars().collect();
+    let first = find_start_marker(&chars, 4);
+    let second = find_start_marker(&chars, 14);
+    (first, second)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fs::read_to_string;
+
+    fn read_file(name: &str) -> String {
+        read_to_string(name).expect(&format!("Unable to read file: {name}")[..]).trim().to_string()
+    }
+
+    #[test]
+    fn test_sample() {
+        let sample_input = read_file("tests/sample_input");
+        assert_eq!(run(&sample_input), (Some(7), Some(19)));
+    }
+
+    #[test]
+    fn test_challenge() {
+        let challenge_input = read_file("tests/challenge_input");
+        assert_eq!(run(&challenge_input), (Some(1702), Some(3559)));
+    }
+}

2022/day06-turning_trouble/src/main.rs

@@ -1,46 +0,0 @@
-use std::fs;
-
-fn read_file(path: &str) -> String {
-    fs::read_to_string(path)
-        .expect("File not Found")
-}
-
-fn find_start_marker(message: &Vec<char>, distinct_character_count: usize) -> usize {
-    'char_iterator: for index in distinct_character_count-1..message.len() {
-        let mut found: Vec<char> = Vec::with_capacity(distinct_character_count);
-        for offset in 0..distinct_character_count {
-            let this_char = message[index+offset+1-distinct_character_count];
-            if found.contains(&this_char) { continue 'char_iterator; }
-            found.push(this_char);
-        }
-        return index+1;
-    }
-    panic!("No start found");
-}
-
-fn main() {
-    //let datastream = read_file("sample_input");
-    let datastream = read_file("input");
-
-    let chars = datastream.chars().collect::<Vec<char>>();
-    println!("Start of Packet: {}", find_start_marker(&chars, 4));
-    println!("Start of Message: {}", find_start_marker(&chars, 14));
-}
-
-#[test]
-fn sample_input() {
-    let datastream = read_file("tests/sample_input");
-
-    let chars = datastream.chars().collect::<Vec<_>>();
-    assert_eq!(find_start_marker(&chars, 4), 7);
-    assert_eq!(find_start_marker(&chars, 14), 19);
-}
-
-#[test]
-fn challenge_input() {
-    let datastream = read_file("tests/input");
-
-    let chars = datastream.chars().collect::<Vec<_>>();
-    assert_eq!(find_start_marker(&chars, 4), 1702);
-    assert_eq!(find_start_marker(&chars, 14), 3559);
-}