diff --git a/ff/src/lib.rs b/ff/src/lib.rs
index ebec847c7..e54eb7bfd 100644
--- a/ff/src/lib.rs
+++ b/ff/src/lib.rs
@@ -342,7 +342,7 @@ impl<E: AsRef<[u64]>> Iterator for BitIterator<E> {
 
 #[test]
 fn test_bit_iterator() {
-    let mut a = BitIterator::new([0xa953d79b83f6ab59, 0x6dea2059e200bd39]);
+    let mut a = BitIterator::new([0xa953_d79b_83f6_ab59, 0x6dea_2059_e200_bd39]);
     let expected = "01101101111010100010000001011001111000100000000010111101001110011010100101010011110101111001101110000011111101101010101101011001";
 
     for e in expected.chars() {
@@ -354,10 +354,10 @@ fn test_bit_iterator() {
     let expected = "1010010101111110101010000101101011101000011101110101001000011001100100100011011010001011011011010001011011101100110100111011010010110001000011110100110001100110011101101000101100011100100100100100001010011101010111110011101011000011101000111011011101011001";
 
     let mut a = BitIterator::new([
-        0x429d5f3ac3a3b759,
-        0xb10f4c66768b1c92,
-        0x92368b6d16ecd3b4,
-        0xa57ea85ae8775219,
+        0x429d_5f3a_c3a3_b759,
+        0xb10f_4c66_768b_1c92,
+        0x9236_8b6d_16ec_d3b4,
+        0xa57e_a85a_e877_5219,
     ]);
 
     for e in expected.chars() {