diff --git a/src/main.rs b/src/main.rs
index a2c775b..bad9f33 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -25,11 +25,9 @@ trait Peristance {
 
 impl Peristance for BigUint {  
     fn per_mul(&self) -> u8 {
-        let mut n = self.to_radix_le(10)
-            .into_iter()
-            .product::<BigUint>();
+        let mut n = self.clone();
 
-        let mut counter = 1;
+        let mut counter = 0;
         while n.to_str_radix(10).chars().count() > 1 {
             n = n.to_radix_le(10)
                 .into_iter()
@@ -112,3 +110,28 @@ fn main() {
     println!("Finding took {:#?}", start.elapsed());
     return;
 }
+
+
+
+
+#[cfg(test)]
+mod tests {
+    // Note this useful idiom: importing names from outer (for mod tests) scope.
+    use super::*;
+
+    #[test]
+    fn test_persistance() {
+        assert_eq!(BigUint::from(0u8).per_mul(), 0);
+        assert_eq!(BigUint::from(10u8).per_mul(), 1);
+        assert_eq!(BigUint::from(25u8).per_mul(), 2);
+        assert_eq!(BigUint::from(39u8).per_mul(), 3);
+        assert_eq!(BigUint::from(77u8).per_mul(), 4);
+        assert_eq!(BigUint::from(679u16).per_mul(), 5);
+        assert_eq!(BigUint::from(6788u16).per_mul(), 6);
+        assert_eq!(BigUint::from(68889u32).per_mul(), 7);
+        assert_eq!(BigUint::from(2677889u32).per_mul(), 8);
+        assert_eq!(BigUint::from(26888999u32).per_mul(), 9);
+        assert_eq!(BigUint::from(3778888999u32).per_mul(), 10);
+        assert_eq!(BigUint::from(277777788888899u64).per_mul(), 11);
+    }
+}