Make Test Helpers no_std Compatible (#823)

* Use `sp-application-crypto` when generating test justifications

* Try to justifications tests compiling

* Try using `ed25519_dalek` for justification creation

* Small cleanup

* Correctly generate a Keypair

The public key didn't correspond to what would be derived
with the given private key.

* Remove enum index hack

* Clean up test account helper functions

* Fix tests in `pallet-finality-verifier`

* Get `pallet-substrate-bridge` tests compiling again

* Use the correct keyring in justification tests

* Clean up Keyring related code a bit

* Appease Clippy

* Remove unused import

* Use keyring variants directly

* Remove unecessary From implementation

bridges/primitives/test-utils/src/lib.rs

@@ -15,18 +15,18 @@
 // along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
 
 //! Utilities for testing runtime code.
-//!
-//! Unlike other crates in the `primitives` folder, this crate does *not* need to compile in a
-//! `no_std` environment. This is fine because this code should only be used, as the name implies,
-//! in tests.
+
+#![cfg_attr(not(feature = "std"), no_std)]
 
 use bp_header_chain::justification::GrandpaJustification;
+use ed25519_dalek::{Keypair, PublicKey, SecretKey, Signature, Signer};
 use finality_grandpa::voter_set::VoterSet;
+use sp_application_crypto::{Public, TryFrom};
 use sp_finality_grandpa::{AuthorityId, AuthorityList, AuthorityWeight};
 use sp_finality_grandpa::{AuthoritySignature, SetId};
-use sp_keyring::Ed25519Keyring;
-use sp_runtime::traits::Header as HeaderT;
-use sp_runtime::traits::{One, Zero};
+use sp_runtime::traits::{Header as HeaderT, One, Zero};
+use sp_runtime::RuntimeDebug;
+use sp_std::prelude::*;
 
 pub const TEST_GRANDPA_ROUND: u64 = 1;
 pub const TEST_GRANDPA_SET_ID: SetId = 1;
@@ -37,7 +37,7 @@ pub fn make_justification_for_header<H: HeaderT>(
 	header: &H,
 	round: u64,
 	set_id: SetId,
-	authorities: &[(AuthorityId, AuthorityWeight)],
+	authorities: &[(Keyring, AuthorityWeight)],
 ) -> GrandpaJustification<H> {
 	let (target_hash, target_number) = (header.hash(), *header.number());
 	let mut precommits = vec![];
@@ -51,13 +51,7 @@ pub fn make_justification_for_header<H: HeaderT>(
 	// I'm using the same header for all the voters since it doesn't matter as long
 	// as they all vote on blocks _ahead_ of the one we're interested in finalizing
 	for (id, _weight) in authorities.iter() {
-		let signer = extract_keyring(&id);
-		let precommit = signed_precommit::<H>(
-			signer,
-			(precommit_header.hash(), *precommit_header.number()),
-			round,
-			set_id,
-		);
+		let precommit = signed_precommit::<H>(id, (precommit_header.hash(), *precommit_header.number()), round, set_id);
 		precommits.push(precommit);
 		votes_ancestries.push(precommit_header.clone());
 	}
@@ -74,7 +68,7 @@ pub fn make_justification_for_header<H: HeaderT>(
 }
 
 fn signed_precommit<H: HeaderT>(
-	signer: Ed25519Keyring,
+	signer: &Keyring,
 	target: (H::Hash, H::Number),
 	round: u64,
 	set_id: SetId,
@@ -83,13 +77,24 @@ fn signed_precommit<H: HeaderT>(
 		target_hash: target.0,
 		target_number: target.1,
 	};
+
 	let encoded =
 		sp_finality_grandpa::localized_payload(round, set_id, &finality_grandpa::Message::Precommit(precommit.clone()));
-	let signature = signer.sign(&encoded[..]).into();
+
+	let signature = signer.pair().sign(&encoded);
+	let raw_signature: Vec<u8> = signature.to_bytes().into();
+
+	// Need to wrap our signature and id types that they match what our `SignedPrecommit` is expecting
+	let signature = AuthoritySignature::try_from(raw_signature).expect(
+		"We know our Keypair is good,
+		so our signature must also be good.",
+	);
+	let id = (*signer).into();
+
 	finality_grandpa::SignedPrecommit {
 		precommit,
 		signature,
-		id: signer.public().into(),
+		id,
 	}
 }
 
@@ -118,11 +123,47 @@ pub fn header_id<H: HeaderT>(index: u8) -> (H::Hash, H::Number) {
 	(test_header::<H>(index.into()).hash(), index.into())
 }
 
-/// Get the identity of a test account given an ED25519 Public key.
-pub fn extract_keyring(id: &AuthorityId) -> Ed25519Keyring {
-	let mut raw_public = [0; 32];
-	raw_public.copy_from_slice(id.as_ref());
-	Ed25519Keyring::from_raw_public(raw_public).unwrap()
+/// Set of test accounts.
+#[derive(RuntimeDebug, Clone, Copy)]
+pub enum Keyring {
+	Alice,
+	Bob,
+	Charlie,
+	Dave,
+	Eve,
+	Ferdie,
+}
+
+impl Keyring {
+	pub fn public(&self) -> PublicKey {
+		(&self.secret()).into()
+	}
+
+	pub fn secret(&self) -> SecretKey {
+		SecretKey::from_bytes(&[*self as u8; 32]).expect("A static array of the correct length is a known good.")
+	}
+
+	pub fn pair(self) -> Keypair {
+		let mut pair: [u8; 64] = [0; 64];
+
+		let secret = self.secret();
+		pair[..32].copy_from_slice(&secret.to_bytes());
+
+		let public = self.public();
+		pair[32..].copy_from_slice(&public.to_bytes());
+
+		Keypair::from_bytes(&pair).expect("We expect the SecretKey to be good, so this must also be good.")
+	}
+
+	pub fn sign(self, msg: &[u8]) -> Signature {
+		self.pair().sign(msg)
+	}
+}
+
+impl From<Keyring> for AuthorityId {
+	fn from(k: Keyring) -> Self {
+		AuthorityId::from_slice(&k.public().to_bytes())
+	}
 }
 
 /// Get a valid set of voters for a Grandpa round.
@@ -132,20 +173,10 @@ pub fn voter_set() -> VoterSet<AuthorityId> {
 
 /// Convenience function to get a list of Grandpa authorities.
 pub fn authority_list() -> AuthorityList {
-	vec![(alice(), 1), (bob(), 1), (charlie(), 1)]
+	keyring().iter().map(|(id, w)| (AuthorityId::from(*id), *w)).collect()
 }
 
-/// Get the Public key of the Alice test account.
-pub fn alice() -> AuthorityId {
-	Ed25519Keyring::Alice.public().into()
-}
-
-/// Get the Public key of the Bob test account.
-pub fn bob() -> AuthorityId {
-	Ed25519Keyring::Bob.public().into()
-}
-
-/// Get the Public key of the Charlie test account.
-pub fn charlie() -> AuthorityId {
-	Ed25519Keyring::Charlie.public().into()
+/// Get the corresponding identities from the keyring for the "standard" authority set.
+pub fn keyring() -> Vec<(Keyring, u64)> {
+	vec![(Keyring::Alice, 1), (Keyring::Bob, 1), (Keyring::Charlie, 1)]
 }