From 8e2319f4ff88614ffdf38a86de7c846cc7b03ca1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bastian=20K=C3=B6cher?= <bkchr@users.noreply.github.com>
Date: Wed, 26 Aug 2020 09:05:49 +0200
Subject: [PATCH] Remove implementation of `Randomness for ()` (#6959)

---
 frame/society/src/mock.rs   | 5 +++--
 frame/support/src/traits.rs | 5 ++++-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/frame/society/src/mock.rs b/frame/society/src/mock.rs
index f29dbc8cb17ad..1ca828bf37196 100644
--- a/frame/society/src/mock.rs
+++ b/frame/society/src/mock.rs
@@ -20,7 +20,8 @@
 use super::*;
 
 use frame_support::{
-	impl_outer_origin, parameter_types, ord_parameter_types, traits::{OnInitialize, OnFinalize}
+	impl_outer_origin, parameter_types, ord_parameter_types,
+	traits::{OnInitialize, OnFinalize, TestRandomness},
 };
 use sp_core::H256;
 use sp_runtime::{
@@ -99,7 +100,7 @@ impl pallet_balances::Trait for Test {
 impl Trait for Test {
 	type Event = ();
 	type Currency = pallet_balances::Module<Self>;
-	type Randomness = ();
+	type Randomness = TestRandomness;
 	type CandidateDeposit = CandidateDeposit;
 	type WrongSideDeduction = WrongSideDeduction;
 	type MaxStrikes = MaxStrikes;
diff --git a/frame/support/src/traits.rs b/frame/support/src/traits.rs
index 72a3850d2d37e..6f50f38a23369 100644
--- a/frame/support/src/traits.rs
+++ b/frame/support/src/traits.rs
@@ -1345,7 +1345,10 @@ pub trait Randomness<Output> {
 	}
 }
 
-impl<Output: Decode + Default> Randomness<Output> for () {
+/// Provides an implementation of [`Randomness`] that should only be used in tests!
+pub struct TestRandomness;
+
+impl<Output: Decode + Default> Randomness<Output> for TestRandomness {
 	fn random(subject: &[u8]) -> Output {
 		Output::decode(&mut TrailingZeroInput::new(subject)).unwrap_or_default()
 	}