diff --git a/util/src/uint.rs b/util/src/uint.rs
index 82d3afe97..245381b4b 100644
--- a/util/src/uint.rs
+++ b/util/src/uint.rs
@@ -1489,5 +1489,32 @@ mod tests {
         let (_, overflow) = U256([0, 0, 0, ::std::u64::MAX]).overflowing_add(U256([0, 0, 0, ::std::u64::MAX]));
         assert!(overflow);
     }
+
+
+    #[test]
+    fn u256_multi_subs() {
+        let (result, _) = U256([0, 0, 0, 0]).overflowing_sub(U256([0, 0, 0, 0]));
+        assert_eq!(result, U256([0, 0, 0, 0]));
+
+        let (result, _) = U256([0, 0, 0, 1]).overflowing_sub(U256([0, 0, 0, 1]));
+        assert_eq!(result, U256([0, 0, 0, 0]));
+
+        let (_, overflow) = U256([0, 0, 2, 1]).overflowing_sub(U256([0, 0, 3, 1]));
+        assert!(overflow);
+
+        let (result, overflow) = U256([::std::u64::MAX, ::std::u64::MAX, ::std::u64::MAX, ::std::u64::MAX])
+                                .overflowing_sub(U256([::std::u64::MAX/2, ::std::u64::MAX/2, ::std::u64::MAX/2, ::std::u64::MAX/2]));
+        assert!(!overflow);
+        assert_eq!(U256([::std::u64::MAX/2+1, ::std::u64::MAX/2+1, ::std::u64::MAX/2+1, ::std::u64::MAX/2+1]), result);
+
+        let (result, overflow) = U256([0, 0, 0, 1]).overflowing_sub(U256([0, 0, 1, 0]));
+        assert!(!overflow);
+        assert_eq!(U256([0, 0, ::std::u64::MAX, 0]), result);
+
+        let (result, overflow) = U256([0, 0, 0, 1]).overflowing_sub(U256([1, 0, 0, 0]));
+        assert!(!overflow);
+        assert_eq!(U256([::std::u64::MAX, ::std::u64::MAX, ::std::u64::MAX, 0]), result);
+    }
+
 }