From 11b1dc142fb31a730ebb98aa8ce2e604cd04a4cc Mon Sep 17 00:00:00 2001
From: Sean Bowe <ewillbefull@gmail.com>
Date: Sat, 30 Jun 2018 09:49:54 -0600
Subject: [PATCH] Add test for behavior of Scalar::batch_invert().

---
 src/scalar.rs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/scalar.rs b/src/scalar.rs
index 5b67732..15c8b7c 100644
--- a/src/scalar.rs
+++ b/src/scalar.rs
@@ -1138,4 +1138,20 @@ mod test {
         // This should panic in debug mode.
         Scalar::batch_invert(&mut xs);
     }
+
+    #[test]
+    fn batch_invert_consistency() {
+        let mut x = Scalar::from_u64(1);
+        let mut v1: Vec<_> = (0..16).map(|_| {let tmp = x; x = x + x; tmp}).collect();
+        let v2 = v1.clone();
+
+        let expected: Scalar = v1.iter().product();
+        let expected = expected.invert();
+        let ret = Scalar::batch_invert(&mut v1);
+        assert_eq!(ret, expected);
+
+        for (a, b) in v1.iter().zip(v2.iter()) {
+            assert_eq!(a * b, Scalar::one());
+        }
+    }
 }