From 176c77d60297f36085be6201f8db5f9da3a1f6a5 Mon Sep 17 00:00:00 2001
From: Sean Bowe <ewillbefull@gmail.com>
Date: Tue, 18 Jul 2017 11:18:42 -0600
Subject: [PATCH] Random encoding/decoding tests for `PrimeFieldRepr`. Closes
 #3.

---
 src/bls12_381/fq.rs |  5 +++++
 src/bls12_381/fr.rs |  5 +++++
 src/lib.rs          |  1 +
 src/tests/mod.rs    |  1 +
 src/tests/repr.rs   | 21 +++++++++++++++++++++
 5 files changed, 33 insertions(+)
 create mode 100644 src/tests/repr.rs

diff --git a/src/bls12_381/fq.rs b/src/bls12_381/fq.rs
index 00b0405..e7be0ec 100644
--- a/src/bls12_381/fq.rs
+++ b/src/bls12_381/fq.rs
@@ -1750,3 +1750,8 @@ fn test_fq_ordering() {
         assert!(Fq::from_repr(FqRepr::from(i+1)).unwrap() > Fq::from_repr(FqRepr::from(i)).unwrap());
     }
 }
+
+#[test]
+fn fq_repr_tests() {
+    ::tests::repr::random_repr_tests::<FqRepr>();
+}
diff --git a/src/bls12_381/fr.rs b/src/bls12_381/fr.rs
index c321b76..63cc264 100644
--- a/src/bls12_381/fr.rs
+++ b/src/bls12_381/fr.rs
@@ -1453,3 +1453,8 @@ fn fr_field_tests() {
     ::tests::field::random_sqrt_tests::<Fr>();
     ::tests::field::random_frobenius_tests::<Fr, _>(Fr::char(), 13);
 }
+
+#[test]
+fn fr_repr_tests() {
+    ::tests::repr::random_repr_tests::<FrRepr>();
+}
diff --git a/src/lib.rs b/src/lib.rs
index 04bde0f..ca38451 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -332,6 +332,7 @@ pub trait PrimeFieldRepr: Sized +
                           Ord +
                           Send +
                           Sync +
+                          Default +
                           fmt::Debug +
                           fmt::Display +
                           'static +
diff --git a/src/tests/mod.rs b/src/tests/mod.rs
index 2cb00a7..cf00add 100644
--- a/src/tests/mod.rs
+++ b/src/tests/mod.rs
@@ -1,3 +1,4 @@
 pub mod curve;
 pub mod field;
 pub mod engine;
+pub mod repr;
diff --git a/src/tests/repr.rs b/src/tests/repr.rs
new file mode 100644
index 0000000..b0c119c
--- /dev/null
+++ b/src/tests/repr.rs
@@ -0,0 +1,21 @@
+use rand::{SeedableRng, XorShiftRng};
+use ::{PrimeFieldRepr};
+
+pub fn random_repr_tests<R: PrimeFieldRepr>() {
+	random_encoding_tests::<R>();
+}
+
+fn random_encoding_tests<R: PrimeFieldRepr>() {
+	let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
+
+	for _ in 0..1000 {
+		let r = R::rand(&mut rng);
+		let mut rdecoded = R::default();
+
+		let mut v: Vec<u8> = vec![];
+		r.write_be(&mut v).unwrap();
+		rdecoded.read_be(&v[0..]).unwrap();
+
+		assert_eq!(r, rdecoded);
+	}
+}