diff --git a/src/day06.rs b/src/day06.rs
index 6d3b968..90d72e3 100644
--- a/src/day06.rs
+++ b/src/day06.rs
@@ -8,11 +8,11 @@ fn count_babies(birthday: isize, end_day: isize) -> usize {
     1 + (birthday..=end_day)
         .skip(2 + 7)
         .step_by(7)
-        .map(|day| count_babies(day, end_day) as usize)
+        .map(|day| count_babies(day, end_day))
         .sum::<usize>()
 }
 
-fn count_population(pop: &Vec<isize>, end_day: isize) -> usize {
+fn count_population(pop: &[isize], end_day: isize) -> usize {
     pop.iter().map(|d| count_babies(d - 8, end_day)).sum()
 }
 
@@ -26,7 +26,7 @@ mod tests {
     use super::*;
 
     #[test]
-    fn emit_babies() {
+    fn test_count_babies() {
         assert_eq!(count_babies(3 - 8, 18), 5);
     }
 
@@ -42,5 +42,6 @@ mod tests {
     fn test_my_data() {
         let data = parse_by_char::<isize>(include_str!("../data/day06.txt"), ',').unwrap();
         assert_eq!(count_population(&data, 80), 358214);
+        assert_eq!(count_population(&data, 256), 1622533344325);
     }
 }