diff --git a/2023/day1/input_small1.txt b/2023/day1/input_small1.txt
new file mode 100644
index 0000000..7bbc69a
--- /dev/null
+++ b/2023/day1/input_small1.txt
@@ -0,0 +1,4 @@
+1abc2
+pqr3stu8vwx
+a1b2c3d4e5f
+treb7uchet
diff --git a/2023/day1/input_small2.txt b/2023/day1/input_small2.txt
new file mode 100644
index 0000000..41aa89c
--- /dev/null
+++ b/2023/day1/input_small2.txt
@@ -0,0 +1,7 @@
+two1nine
+eightwothree
+abcone2threexyz
+xtwone3four
+4nineeightseven2
+zoneight234
+7pqrstsixteen
diff --git a/2023/day1/src/branchless.rs b/2023/day1/src/branchless.rs
index b2df058..9480dfd 100644
--- a/2023/day1/src/branchless.rs
+++ b/2023/day1/src/branchless.rs
@@ -1,4 +1,4 @@
-pub unsafe fn part2(input: &str) {
+pub unsafe fn part2(input: &str) -> u64 {
     let sum = input
         .lines()
         .map(|line| {
@@ -73,5 +73,5 @@ pub unsafe fn part2(input: &str) {
         })
         .sum::<u64>();
 
-    println!("part2: {sum}");
+    sum
 }
diff --git a/2023/day1/src/main.rs b/2023/day1/src/main.rs
index f0ba9a5..d9ff957 100644
--- a/2023/day1/src/main.rs
+++ b/2023/day1/src/main.rs
@@ -1,5 +1,7 @@
 use std::mem::MaybeUninit;
 
+use helper::{Day, Variant, Variants};
+
 mod branchless;
 mod naive;
 mod no_lines;
@@ -30,10 +32,41 @@ fn main() {
             eprintln!("error: invalid mode, must be part1,naive,zero_alloc,branchless");
             std::process::exit(1);
         }
+    };
+}
+
+struct Day1;
+
+impl Day for Day1 {
+    fn pad_input(input: &str) -> std::borrow::Cow<str> {
+        let mut input = input.to_owned();
+        input.reserve(10); // enough to read u64
+        unsafe {
+            input
+                .as_mut_vec()
+                .spare_capacity_mut()
+                .fill(MaybeUninit::new(0))
+        };
+        std::borrow::Cow::Owned(input)
+    }
+    fn part1() -> Variants {
+        Variants::basic(part1)
+    }
+
+    fn part2() -> Variants {
+        Variants {
+            variants: vec![
+                Variant::new("naive", naive::part2),
+                Variant::new("zero_alloc", zero_alloc::part2),
+                Variant::new("branchless", |i| unsafe { branchless::part2(i) }),
+                Variant::new("no_lines", |i| unsafe { no_lines::part2(i) }),
+                Variant::new("vectorized", |i| unsafe { vectorized::part2(i) }),
+            ],
+        }
     }
 }
 
-fn part1(input: &str) {
+fn part1(input: &str) -> u64 {
     let sum = input
         .lines()
         .map(|line| {
@@ -49,5 +82,17 @@ fn part1(input: &str) {
         })
         .sum::<u64>();
 
-    println!("part1: {sum}");
+    sum
+}
+
+helper::tests! {
+    day1 Day1;
+    part1 {
+        "../input_small1.txt" => 142;
+        "../input.txt" => 54632;
+    }
+    part2 {
+        "../input_small2.txt" => 281;
+        "../input.txt" => 54019;
+    }
 }
diff --git a/2023/day1/src/naive.rs b/2023/day1/src/naive.rs
index c835fa4..3b74b79 100644
--- a/2023/day1/src/naive.rs
+++ b/2023/day1/src/naive.rs
@@ -1,4 +1,4 @@
-pub fn part2(input: &str) {
+pub fn part2(input: &str) -> u64 {
     let sum = input
         .lines()
         .map(|line| {
@@ -24,5 +24,5 @@ pub fn part2(input: &str) {
         })
         .sum::<u64>();
 
-    println!("part2: {sum}");
-}
+        sum
+    }
diff --git a/2023/day1/src/no_lines.rs b/2023/day1/src/no_lines.rs
index 8a16c81..abdc37d 100644
--- a/2023/day1/src/no_lines.rs
+++ b/2023/day1/src/no_lines.rs
@@ -1,4 +1,4 @@
-pub unsafe fn part2(input: &str) {
+pub unsafe fn part2(input: &str) -> u64 {
     let mut sum = 0;
 
     let bytes = input.as_bytes();
@@ -83,5 +83,5 @@ pub unsafe fn part2(input: &str) {
         line_idx += 1;
     }
 
-    println!("part2: {sum}");
+    sum
 }
diff --git a/2023/day1/src/vectorized.rs b/2023/day1/src/vectorized.rs
index 80875ec..7ad9f51 100644
--- a/2023/day1/src/vectorized.rs
+++ b/2023/day1/src/vectorized.rs
@@ -1,4 +1,4 @@
-pub unsafe fn part2(input: &str) {
+pub unsafe fn part2(input: &str) -> u64 {
     let mut sum = 0;
 
     let bytes = input.as_bytes();
@@ -152,5 +152,5 @@ pub unsafe fn part2(input: &str) {
         line_idx += 1;
     }
 
-    println!("part2: {sum}");
+    sum
 }
diff --git a/2023/day1/src/zero_alloc.rs b/2023/day1/src/zero_alloc.rs
index 8a6b9c4..8f5b2d2 100644
--- a/2023/day1/src/zero_alloc.rs
+++ b/2023/day1/src/zero_alloc.rs
@@ -1,4 +1,4 @@
-pub fn part2(input: &str) {
+pub fn part2(input: &str) -> u64 {
     let sum = input
         .lines()
         .map(|line| {
@@ -39,5 +39,5 @@ pub fn part2(input: &str) {
         })
         .sum::<u64>();
 
-    println!("part2: {sum}");
-}
+        sum
+    }
diff --git a/helper/src/lib.rs b/helper/src/lib.rs
index 7b183b5..6e91601 100644
--- a/helper/src/lib.rs
+++ b/helper/src/lib.rs
@@ -33,6 +33,12 @@ impl Variants {
     }
 }
 
+impl Variant {
+    pub fn new(name: &'static str, f: Solution) -> Self {
+        Self { name, f }
+    }
+}
+
 pub fn test_part1<D: Day>(inputs: &[(&str, u64)]) {
     for variant in D::part1().variants {
         for input in inputs {
@@ -67,22 +73,49 @@ macro_rules! tests {
             small => $p2small:expr;
             default => $p2default:expr;
         }
+    ) => {
+        $crate::tests! {
+            $day_small $day;
+            part1 {
+                "../input_small.txt" => $p1small;
+                "../input.txt" => $p1default;
+            }
+            part2 {
+                "../input_small.txt" => $p2small;
+                "../input.txt" => $p2default;
+            }
+        }
+    };
+    (
+        $day_small:ident $day:ident;
+        part1 {
+            $(
+                $file1:literal => $p1:expr;
+            )*
+        }
+        part2 {
+            $(
+                $file2:literal => $p2:expr;
+            )*
+        }
     ) => {
         #[cfg(test)]
         mod $day_small {
             #[test]
             fn part1() {
                 helper::test_part1::<super::$day>(&[
-                    (include_str!("../input_small.txt"), $p1small),
-                    (include_str!("../input.txt"), $p1default),
+                    $(
+                        (include_str!($file1), $p1),
+                    )*
                 ]);
             }
 
             #[test]
             fn part2() {
                 helper::test_part2::<super::$day>(&[
-                    (include_str!("../input_small.txt"), $p2small),
-                    (include_str!("../input.txt"), $p2default),
+                    $(
+                        (include_str!($file2), $p2),
+                    )*
                 ]);
             }
         }