diff --git a/complex/src/lib.rs b/complex/src/lib.rs
index 9ab4ef9..e43525e 100644
--- a/complex/src/lib.rs
+++ b/complex/src/lib.rs
@@ -870,6 +870,7 @@ mod test {
     pub const _neg1_1i : Complex64 = Complex { re: -1.0, im: 1.0 };
     pub const _05_05i : Complex64 = Complex { re: 0.5, im: 0.5 };
     pub const all_consts : [Complex64; 5] = [_0_0i, _1_0i, _1_1i, _neg1_1i, _05_05i];
+    pub const _4_2i : Complex64 = Complex { re: 4.0, im: 2.0 };
 
     #[test]
     fn test_consts() {
@@ -1299,55 +1300,83 @@ mod test {
         }
     }
 
+    // Test both a + b and a += b
+    macro_rules! test_a_op_b {
+        ($a:ident + $b:expr, $answer:expr) => {
+            assert_eq!($a + $b, $answer);
+            assert_eq!({ let mut x = $a; x += $b; x}, $answer);
+        };
+        ($a:ident - $b:expr, $answer:expr) => {
+            assert_eq!($a - $b, $answer);
+            assert_eq!({ let mut x = $a; x -= $b; x}, $answer);
+        };
+        ($a:ident * $b:expr, $answer:expr) => {
+            assert_eq!($a * $b, $answer);
+            assert_eq!({ let mut x = $a; x *= $b; x}, $answer);
+        };
+        ($a:ident / $b:expr, $answer:expr) => {
+            assert_eq!($a / $b, $answer);
+            assert_eq!({ let mut x = $a; x /= $b; x}, $answer);
+        };
+    }
+
+    // Test both a + b and a + &b
+    macro_rules! test_op {
+        ($a:ident $op:tt $b:expr, $answer:expr) => {
+            test_a_op_b!($a $op $b, $answer);
+            test_a_op_b!($a $op &$b, $answer);
+        }
+    }
+
     mod complex_arithmetic {
         use super::{_0_0i, _1_0i, _1_1i, _0_1i, _neg1_1i, _05_05i, all_consts};
         use traits::Zero;
 
         #[test]
         fn test_add() {
-            assert_eq!(_05_05i + _05_05i, _1_1i);
-            assert_eq!(_0_1i + _1_0i, _1_1i);
-            assert_eq!(_1_0i + _neg1_1i, _0_1i);
+            test_op!(_05_05i + _05_05i, _1_1i);
+            test_op!(_0_1i + _1_0i, _1_1i);
+            test_op!(_1_0i + _neg1_1i, _0_1i);
 
             for &c in all_consts.iter() {
-                assert_eq!(_0_0i + c, c);
-                assert_eq!(c + _0_0i, c);
+                test_op!(_0_0i + c, c);
+                test_op!(c + _0_0i, c);
             }
         }
 
         #[test]
         fn test_sub() {
-            assert_eq!(_05_05i - _05_05i, _0_0i);
-            assert_eq!(_0_1i - _1_0i, _neg1_1i);
-            assert_eq!(_0_1i - _neg1_1i, _1_0i);
+            test_op!(_05_05i - _05_05i, _0_0i);
+            test_op!(_0_1i - _1_0i, _neg1_1i);
+            test_op!(_0_1i - _neg1_1i, _1_0i);
 
             for &c in all_consts.iter() {
-                assert_eq!(c - _0_0i, c);
-                assert_eq!(c - c, _0_0i);
+                test_op!(c - _0_0i, c);
+                test_op!(c - c, _0_0i);
             }
         }
 
         #[test]
         fn test_mul() {
-            assert_eq!(_05_05i * _05_05i, _0_1i.unscale(2.0));
-            assert_eq!(_1_1i * _0_1i, _neg1_1i);
+            test_op!(_05_05i * _05_05i, _0_1i.unscale(2.0));
+            test_op!(_1_1i * _0_1i, _neg1_1i);
 
             // i^2 & i^4
-            assert_eq!(_0_1i * _0_1i, -_1_0i);
+            test_op!(_0_1i * _0_1i, -_1_0i);
             assert_eq!(_0_1i * _0_1i * _0_1i * _0_1i, _1_0i);
 
             for &c in all_consts.iter() {
-                assert_eq!(c * _1_0i, c);
-                assert_eq!(_1_0i * c, c);
+                test_op!(c * _1_0i, c);
+                test_op!(_1_0i * c, c);
             }
         }
 
         #[test]
         fn test_div() {
-            assert_eq!(_neg1_1i / _0_1i, _1_1i);
+            test_op!(_neg1_1i / _0_1i, _1_1i);
             for &c in all_consts.iter() {
                 if c != Zero::zero() {
-                    assert_eq!(c / c, _1_0i);
+                    test_op!(c / c, _1_0i);
                 }
             }
         }
@@ -1364,29 +1393,30 @@ mod test {
 
     mod real_arithmetic {
         use super::super::Complex;
+        use super::_4_2i;
 
         #[test]
         fn test_add() {
-            assert_eq!(Complex::new(4.0, 2.0) + 0.5, Complex::new(4.5, 2.0));
-            assert_eq!(0.5 + Complex::new(4.0, 2.0), Complex::new(4.5, 2.0));
+            test_op!(_4_2i + 0.5, Complex::new(4.5, 2.0));
+            assert_eq!(0.5 + _4_2i, Complex::new(4.5, 2.0));
         }
 
         #[test]
         fn test_sub() {
-            assert_eq!(Complex::new(4.0, 2.0) - 0.5, Complex::new(3.5, 2.0));
-            assert_eq!(0.5 - Complex::new(4.0, 2.0), Complex::new(-3.5, -2.0));
+            test_op!(_4_2i - 0.5, Complex::new(3.5, 2.0));
+            assert_eq!(0.5 - _4_2i, Complex::new(-3.5, -2.0));
         }
 
         #[test]
         fn test_mul() {
-            assert_eq!(Complex::new(4.0, 2.0) * 0.5, Complex::new(2.0, 1.0));
-            assert_eq!(0.5 * Complex::new(4.0, 2.0), Complex::new(2.0, 1.0));
+            assert_eq!(_4_2i * 0.5, Complex::new(2.0, 1.0));
+            assert_eq!(0.5 * _4_2i, Complex::new(2.0, 1.0));
         }
 
         #[test]
         fn test_div() {
-            assert_eq!(Complex::new(4.0, 2.0) / 0.5, Complex::new(8.0, 4.0));
-            assert_eq!(0.5 / Complex::new(4.0, 2.0), Complex::new(0.1, -0.05));
+            assert_eq!(_4_2i / 0.5, Complex::new(8.0, 4.0));
+            assert_eq!(0.5 / _4_2i, Complex::new(0.1, -0.05));
         }
     }