diff --git a/2022/day10-cathode-ray_tube/src/lib.rs b/2022/day10-cathode-ray_tube/src/lib.rs
new file mode 100644
index 0000000..e2248a3
--- /dev/null
+++ b/2022/day10-cathode-ray_tube/src/lib.rs
@@ -0,0 +1,121 @@
+use core::fmt::Display;
+use std::num::ParseIntError;
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum ParseError<'a> {
+    ParseIntError(std::num::ParseIntError),
+    UnknownInstruction(&'a str),
+}
+
+impl From<ParseIntError> for ParseError<'_> {
+    fn from(value: ParseIntError) -> Self {
+        Self::ParseIntError(value)
+    }
+}
+
+impl Display for ParseError<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::ParseIntError(e) => write!(f, "Unable to parse into integer: {e}"),
+            Self::UnknownInstruction(i) => write!(f, "Tried to parse unknown instruction {i}"),
+        }
+    }
+}
+
+struct Cpu {
+    states: Vec<i32>,
+}
+
+impl <'a> TryFrom<&'a str> for Cpu {
+    type Error = ParseError<'a>;
+
+    fn try_from(value: &'a str) -> Result<Self, Self::Error> {
+        let mut cpu = Cpu { states: vec![1, 1] };
+        for instruction in value.lines() {
+            match &instruction[0..4] {
+                "noop" => cpu.noop(),
+                "addx" => cpu.addx(instruction[5..].parse()?),
+                instr => return Err(Self::Error::UnknownInstruction(instr)),
+            }
+        }
+        Ok(cpu)
+    }
+}
+
+impl Cpu {
+    fn addx(&mut self, x: i32) {
+        let old_state = *self.states.last().unwrap();
+        self.states.push(old_state);
+        self.states.push(old_state + x);
+    }
+
+    fn noop(&mut self) {
+        let old_state = *self.states.last().unwrap();
+        self.states.push(old_state);
+    }
+
+    fn get_rendering(&self) -> String {
+        let mut rendering = String::new();
+        (0..self.states.len()/40).for_each(|line_number| {
+            if line_number != 0 {
+                rendering.push('\n');
+            }
+            let mut this_line = String::new();
+            (0..40).for_each(|col_number| {
+                let clock_cycle = 40*line_number+col_number;
+                if (clock_cycle as i32 % 40 - self.states[clock_cycle + 1]).abs() < 2 {
+                    this_line += "#";
+                } else {
+                    this_line += ".";
+                }
+            });
+            rendering.push_str(&this_line);
+        });
+        rendering
+    }
+}
+
+pub fn run(input: &str) -> Result<(i32, String), ParseError> {
+    let cpu = Cpu::try_from(input)?;
+    let first = [20, 60, 100, 140, 180, 220].iter()
+        .map(|&i| i as i32 * cpu.states[i])
+        .sum();
+    let second = cpu.get_rendering();
+    Ok((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");
+        let expected = &r#"
+##..##..##..##..##..##..##..##..##..##..
+###...###...###...###...###...###...###.
+####....####....####....####....####....
+#####.....#####.....#####.....#####.....
+######......######......######......####
+#######.......#######.......#######....."#[1..];
+        assert_eq!(run(&sample_input), Ok((13140, expected.to_string())));
+    }
+
+    #[test]
+    fn test_challenge() {
+        let challenge_input = read_file("tests/challenge_input");
+        let expected = &r#"
+####.####.###..###..###..####.####.####.
+#.......#.#..#.#..#.#..#.#.......#.#....
+###....#..###..#..#.###..###....#..###..
+#.....#...#..#.###..#..#.#.....#...#....
+#....#....#..#.#....#..#.#....#....#....
+#....####.###..#....###..#....####.#...."#[1..];
+        assert_eq!(run(&challenge_input), Ok((14720, expected.to_string())));
+    }
+}
diff --git a/2022/day10-cathode-ray_tube/src/main.rs b/2022/day10-cathode-ray_tube/src/main.rs
deleted file mode 100644
index 2e0cbbe..0000000
--- a/2022/day10-cathode-ray_tube/src/main.rs
+++ /dev/null
@@ -1,124 +0,0 @@
-use std::fs;
-
-struct Cpu {
-    states: Vec<i32>,
-}
-
-impl Cpu {
-    fn addx(&mut self, x: i32) {
-        let old_state = *self.states.last().unwrap();
-        self.states.push(old_state);
-        self.states.push(old_state + x);
-    }
-
-    fn noop(&mut self) {
-        let old_state = *self.states.last().unwrap();
-        self.states.push(old_state);
-    }
-
-    fn parse(&mut self, instruction: &str) {
-        match &instruction[0..4] {
-            "noop" => self.noop(),
-            "addx" => self.addx(instruction[5..].parse().unwrap()),
-            _ => panic!("Unknown instruction"),
-        }
-    }
-
-    fn get_rendering(&self) -> String {
-        let mut rendering = String::new();
-        (0..self.states.len()/40).for_each(|line_number| {
-            if line_number != 0 {
-                rendering.push('\n');
-            }
-            let mut this_line = String::new();
-            (0..40).for_each(|col_number| {
-                let clock_cycle = 40*line_number+col_number;
-                if (clock_cycle as i32 % 40 - self.states[clock_cycle + 1]).abs() < 2 {
-                    this_line += "#";
-                } else {
-                    this_line += ".";
-                }
-            });
-            rendering.push_str(&this_line);
-        });
-        rendering
-    }
-
-    fn render(&self) {
-        for line_number in 0..self.states.len()/40 {
-            let mut line_string = String::new();
-            for col_number in 0..40 {
-                let clock_cycle = 40*line_number+col_number;
-                if (clock_cycle as i32 % 40 - self.states[clock_cycle + 1]).abs() < 2 {
-                    line_string += "#";
-                } else {
-                    line_string += ".";
-                }
-            }
-            println!("{line_string}");
-        }
-    }
-}
-
-fn read_file(path: &str) -> String {
-    fs::read_to_string(path)
-        .expect("File not Found")
-}
-
-fn main() {
-    //let program = read_file("sample_input");
-    let program = read_file("input");
-
-    let mut cpu = Cpu { states: vec![1, 1], };
-    for instruction in program.lines() {
-        cpu.parse(instruction);
-    }
-    let sum_of_relevant_strengths: i32 = [20, 60, 100, 140, 180, 220].iter()
-        .map(|&i| i as i32 * cpu.states[i])
-        .sum();
-
-    println!("The relevant signal strengths sum up to {sum_of_relevant_strengths}.");
-    cpu.render();
-}
-
-#[test]
-fn sample_input() {
-    let program = read_file("tests/sample_input");
-
-    let mut cpu = Cpu { states: vec![1, 1], };
-    for instruction in program.lines() {
-        cpu.parse(instruction);
-    }
-    let sum_of_relevant_strengths: i32 = [20, 60, 100, 140, 180, 220].iter()
-        .map(|&i| i as i32 * cpu.states[i])
-        .sum();
-
-    assert_eq!(sum_of_relevant_strengths, 13140);
-    assert_eq!(cpu.get_rendering(), r#"##..##..##..##..##..##..##..##..##..##..
-###...###...###...###...###...###...###.
-####....####....####....####....####....
-#####.....#####.....#####.....#####.....
-######......######......######......####
-#######.......#######.......#######....."#);
-}
-
-#[test]
-fn challenge_input() {
-    let program = read_file("tests/input");
-
-    let mut cpu = Cpu { states: vec![1, 1], };
-    for instruction in program.lines() {
-        cpu.parse(instruction);
-    }
-    let sum_of_relevant_strengths: i32 = [20, 60, 100, 140, 180, 220].iter()
-        .map(|&i| i as i32 * cpu.states[i])
-        .sum();
-
-    assert_eq!(sum_of_relevant_strengths, 14720);
-    assert_eq!(cpu.get_rendering(), r#"####.####.###..###..###..####.####.####.
-#.......#.#..#.#..#.#..#.#.......#.#....
-###....#..###..#..#.###..###....#..###..
-#.....#...#..#.###..#..#.#.....#...#....
-#....#....#..#.#....#..#.#....#....#....
-#....####.###..#....###..#....####.#...."#);
-}
diff --git a/2022/day10-cathode-ray_tube/tests/input b/2022/day10-cathode-ray_tube/tests/challenge_input
similarity index 100%
rename from 2022/day10-cathode-ray_tube/tests/input
rename to 2022/day10-cathode-ray_tube/tests/challenge_input