From 0c2869d5420c3f1273d5203633bad931371cbaa2 Mon Sep 17 00:00:00 2001
From: Gav Wood <gav@ethcore.io>
Date: Sat, 16 Jan 2016 16:52:59 +0100
Subject: [PATCH] Tesys for U256 assign ops.

---
 src/uint.rs | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/src/uint.rs b/src/uint.rs
index 89834a85a..00865387d 100644
--- a/src/uint.rs
+++ b/src/uint.rs
@@ -506,6 +506,36 @@ macro_rules! construct_uint {
 			}
 		}
 
+		impl AddAssign<$name> for $name {
+			fn add_assign(&mut self, other: Self) {
+				*self = self.add(other);
+			}
+		}
+
+		impl SubAssign<$name> for $name {
+			fn sub_assign(&mut self, other: Self) {
+				*self = self.sub(other);
+			}
+		}
+
+		impl MulAssign<$name> for $name {
+			fn mul_assign(&mut self, other: Self) {
+				*self = self.mul(other);
+			}
+		}
+
+		impl DivAssign<$name> for $name {
+			fn div_assign(&mut self, other: Self) {
+				*self = self.div(other);
+			}
+		}
+
+		impl RemAssign<$name> for $name {
+			fn rem_assign(&mut self, other: Self) {
+				*self = self.rem(other);
+			}
+		}
+
 		impl BitAnd<$name> for $name {
 			type Output = $name;
 
@@ -776,6 +806,37 @@ mod tests {
 	use std::str::FromStr;
 	use std::num::wrapping::OverflowingOps;
 
+	#[test]
+	pub fn assign_ops() {
+		let x: U256 = x!(69);
+		let y: U256 = x!(42);
+		{
+			let mut z = x;
+			z += y;
+			assert_eq!(z, x + y);
+		}
+		{
+			let mut z = x;
+			z -= y;
+			assert_eq!(z, x - y);
+		}
+		{
+			let mut z = x;
+			z *= y;
+			assert_eq!(z, x * y);
+		}
+		{
+			let mut z = x;
+			z /= y;
+			assert_eq!(z, x / y);
+		}
+		{
+			let mut z = x;
+			z %= y;
+			assert_eq!(z, x % y);
+		}
+	}
+
 	#[test]
 	pub fn uint256_from() {
 		let e = U256([10, 0, 0, 0]);