diff --git a/src/main.rs b/src/main.rs
index a1fd66d..bad9f33 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -121,7 +121,7 @@ mod tests {
 
     #[test]
     fn test_persistance() {
-        assert_eq!(BigUint::from(0u8).per_mul(), 1);
+        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);