Add a testnet similar to sc_network_test. (#852)

* Copy over files

* Most network tests work

* Fix copyrights

* Strip out unneeded pallets

* Update test-runtime and remove unused network test things

* Upgrade test runtime

* Strip more things out of the test runtime

* Bump kusama impl version

polkadot/network/test/src/block_import.rs

@@ -0,0 +1,89 @@
+// Copyright 2020 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Testing block import logic.
+
+use sp_consensus::ImportedAux;
+use sp_consensus::import_queue::{
+	import_single_block, BasicQueue, BlockImportError, BlockImportResult, IncomingBlock,
+};
+use polkadot_test_runtime_client::{self, prelude::*};
+use polkadot_test_runtime_client::runtime::{Block, Hash};
+use sp_runtime::generic::BlockId;
+use super::*;
+
+fn prepare_good_block() -> (TestClient, Hash, u64, PeerId, IncomingBlock<Block>) {
+	let mut client = polkadot_test_runtime_client::new();
+	let block = client.new_block(Default::default()).unwrap().build().unwrap().block;
+	client.import(BlockOrigin::File, block).unwrap();
+
+	let (hash, number) = (client.block_hash(1).unwrap().unwrap(), 1);
+	let header = client.header(&BlockId::Number(1)).unwrap();
+	let justification = client.justification(&BlockId::Number(1)).unwrap();
+	let peer_id = PeerId::random();
+	(client, hash, number, peer_id.clone(), IncomingBlock {
+		hash,
+		header,
+		body: Some(Vec::new()),
+		justification,
+		origin: Some(peer_id.clone()),
+		allow_missing_state: false,
+		import_existing: false,
+	})
+}
+
+#[test]
+fn import_single_good_block_works() {
+	let (_, _hash, number, peer_id, block) = prepare_good_block();
+
+	let mut expected_aux = ImportedAux::default();
+	expected_aux.is_new_best = true;
+
+	match import_single_block(&mut polkadot_test_runtime_client::new(), BlockOrigin::File, block, &mut PassThroughVerifier(true)) {
+		Ok(BlockImportResult::ImportedUnknown(ref num, ref aux, ref org))
+			if *num == number as u32 && *aux == expected_aux && *org == Some(peer_id) => {}
+		r @ _ => panic!("{:?}", r)
+	}
+}
+
+#[test]
+fn import_single_good_known_block_is_ignored() {
+	let (mut client, _hash, number, _, block) = prepare_good_block();
+	match import_single_block(&mut client, BlockOrigin::File, block, &mut PassThroughVerifier(true)) {
+		Ok(BlockImportResult::ImportedKnown(ref n)) if *n == number as u32 => {}
+		_ => panic!()
+	}
+}
+
+#[test]
+fn import_single_good_block_without_header_fails() {
+	let (_, _, _, peer_id, mut block) = prepare_good_block();
+	block.header = None;
+	match import_single_block(&mut polkadot_test_runtime_client::new(), BlockOrigin::File, block, &mut PassThroughVerifier(true)) {
+		Err(BlockImportError::IncompleteHeader(ref org)) if *org == Some(peer_id) => {}
+		_ => panic!()
+	}
+}
+
+#[test]
+fn async_import_queue_drops() {
+	// Perform this test multiple times since it exhibits non-deterministic behavior.
+	for _ in 0..100 {
+		let verifier = PassThroughVerifier(true);
+		let queue = BasicQueue::new(verifier, Box::new(polkadot_test_runtime_client::new()), None, None);
+		drop(queue);
+	}
+}

polkadot/network/test/src/lib.rs

@@ -0,0 +1,875 @@
+// Copyright 2020 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+#![allow(missing_docs)]
+
+#[cfg(test)]
+mod block_import;
+
+use std::{collections::HashMap, pin::Pin, sync::Arc, marker::PhantomData, task::{Poll, Context as FutureContext}};
+
+use libp2p::build_multiaddr;
+use log::trace;
+use sc_network::config::FinalityProofProvider;
+use sp_blockchain::{
+	Result as ClientResult, well_known_cache_keys::{self, Id as CacheKeyId}, Info as BlockchainInfo,
+};
+use sc_client_api::{
+	BlockchainEvents, BlockImportNotification,
+	FinalityNotifications, ImportNotifications,
+	FinalityNotification,
+	backend::{TransactionFor, AuxStore, Backend, Finalizer},
+};
+use sc_block_builder::{BlockBuilder, BlockBuilderProvider};
+use sc_client::LongestChain;
+use sc_network::config::Roles;
+use sp_consensus::block_validation::DefaultBlockAnnounceValidator;
+use sp_consensus::import_queue::{
+	BasicQueue, BoxJustificationImport, Verifier, BoxFinalityProofImport,
+};
+use sp_consensus::block_import::{BlockImport, ImportResult};
+use sp_consensus::Error as ConsensusError;
+use sp_consensus::{BlockOrigin, BlockImportParams, BlockCheckParams, JustificationImport};
+use futures::prelude::*;
+use sc_network::{NetworkWorker, NetworkStateInfo, NetworkService, ReportHandle, config::ProtocolId};
+use sc_network::config::{NetworkConfiguration, TransportConfig, BoxFinalityProofRequestBuilder};
+use libp2p::PeerId;
+use parking_lot::Mutex;
+use sp_core::H256;
+use sc_network::config::{ProtocolConfig, TransactionPool};
+use sp_runtime::generic::BlockId;
+use sp_runtime::traits::{Block as BlockT, Header as HeaderT, NumberFor};
+use sp_runtime::Justification;
+pub use sc_network_test::PassThroughVerifier;
+
+pub use polkadot_test_runtime_client::runtime::{Block, Extrinsic, Hash};
+pub use polkadot_test_runtime_client::{TestClient, TestClientBuilder, TestClientBuilderExt};
+
+pub type PeersFullClient =
+	sc_client::Client<polkadot_test_runtime_client::Backend, polkadot_test_runtime_client::Executor, Block, polkadot_test_runtime_client::runtime::RuntimeApi>;
+pub type PeersLightClient =
+	sc_client::Client<polkadot_test_runtime_client::LightBackend, polkadot_test_runtime_client::LightExecutor, Block, polkadot_test_runtime_client::runtime::RuntimeApi>;
+
+#[derive(Clone)]
+pub enum PeersClient {
+	Full(Arc<PeersFullClient>, Arc<polkadot_test_runtime_client::Backend>),
+	Light(Arc<PeersLightClient>, Arc<polkadot_test_runtime_client::LightBackend>),
+}
+
+impl PeersClient {
+	pub fn as_full(&self) -> Option<Arc<PeersFullClient>> {
+		match *self {
+			PeersClient::Full(ref client, ref _backend) => Some(client.clone()),
+			_ => None,
+		}
+	}
+
+	pub fn as_block_import<Transaction>(&self) -> BlockImportAdapter<Transaction> {
+		match *self {
+			PeersClient::Full(ref client, ref _backend) =>
+				BlockImportAdapter::new_full(client.clone()),
+			PeersClient::Light(ref client, ref _backend) =>
+				BlockImportAdapter::Light(Arc::new(Mutex::new(client.clone())), PhantomData),
+		}
+	}
+
+	pub fn get_aux(&self, key: &[u8]) -> ClientResult<Option<Vec<u8>>> {
+		match *self {
+			PeersClient::Full(ref client, ref _backend) => client.get_aux(key),
+			PeersClient::Light(ref client, ref _backend) => client.get_aux(key),
+		}
+	}
+
+	pub fn info(&self) -> BlockchainInfo<Block> {
+		match *self {
+			PeersClient::Full(ref client, ref _backend) => client.chain_info(),
+			PeersClient::Light(ref client, ref _backend) => client.chain_info(),
+		}
+	}
+
+	pub fn header(&self, block: &BlockId<Block>) -> ClientResult<Option<<Block as BlockT>::Header>> {
+		match *self {
+			PeersClient::Full(ref client, ref _backend) => client.header(block),
+			PeersClient::Light(ref client, ref _backend) => client.header(block),
+		}
+	}
+
+	pub fn justification(&self, block: &BlockId<Block>) -> ClientResult<Option<Justification>> {
+		match *self {
+			PeersClient::Full(ref client, ref _backend) => client.justification(block),
+			PeersClient::Light(ref client, ref _backend) => client.justification(block),
+		}
+	}
+
+	pub fn finality_notification_stream(&self) -> FinalityNotifications<Block> {
+		match *self {
+			PeersClient::Full(ref client, ref _backend) => client.finality_notification_stream(),
+			PeersClient::Light(ref client, ref _backend) => client.finality_notification_stream(),
+		}
+	}
+
+	pub fn import_notification_stream(&self) -> ImportNotifications<Block>{
+		match *self {
+			PeersClient::Full(ref client, ref _backend) => client.import_notification_stream(),
+			PeersClient::Light(ref client, ref _backend) => client.import_notification_stream(),
+		}
+	}
+
+	pub fn finalize_block(
+		&self,
+		id: BlockId<Block>,
+		justification: Option<Justification>,
+		notify: bool
+	) -> ClientResult<()> {
+		match *self {
+			PeersClient::Full(ref client, ref _backend) => client.finalize_block(id, justification, notify),
+			PeersClient::Light(ref client, ref _backend) => client.finalize_block(id, justification, notify),
+		}
+	}
+}
+
+pub struct Peer<D> {
+	pub data: D,
+	client: PeersClient,
+	/// We keep a copy of the verifier so that we can invoke it for locally-generated blocks,
+	/// instead of going through the import queue.
+	verifier: VerifierAdapter<Block>,
+	/// We keep a copy of the block_import so that we can invoke it for locally-generated blocks,
+	/// instead of going through the import queue.
+	block_import: BlockImportAdapter<()>,
+	select_chain: Option<LongestChain<polkadot_test_runtime_client::Backend, Block>>,
+	backend: Option<Arc<polkadot_test_runtime_client::Backend>>,
+	network: NetworkWorker<Block, <Block as BlockT>::Hash>,
+	imported_blocks_stream: Pin<Box<dyn Stream<Item = BlockImportNotification<Block>> + Send>>,
+	finality_notification_stream: Pin<Box<dyn Stream<Item = FinalityNotification<Block>> + Send>>,
+}
+
+impl<D> Peer<D> {
+	/// Get this peer ID.
+	pub fn id(&self) -> PeerId {
+		self.network.service().local_peer_id()
+	}
+
+	/// Returns true if we're major syncing.
+	pub fn is_major_syncing(&self) -> bool {
+		self.network.service().is_major_syncing()
+	}
+
+	// Returns a clone of the local SelectChain, only available on full nodes
+	pub fn select_chain(&self) -> Option<LongestChain<polkadot_test_runtime_client::Backend, Block>> {
+		self.select_chain.clone()
+	}
+
+	/// Returns the number of peers we're connected to.
+	pub fn num_peers(&self) -> usize {
+		self.network.num_connected_peers()
+	}
+
+	/// Returns true if we have no peer.
+	pub fn is_offline(&self) -> bool {
+		self.num_peers() == 0
+	}
+
+	/// Request a justification for the given block.
+	pub fn request_justification(&self, hash: &<Block as BlockT>::Hash, number: NumberFor<Block>) {
+		self.network.service().request_justification(hash, number);
+	}
+
+	/// Announces an important block on the network.
+	pub fn announce_block(&self, hash: <Block as BlockT>::Hash, data: Vec<u8>) {
+		self.network.service().announce_block(hash, data);
+	}
+
+	/// Request explicit fork sync.
+	pub fn set_sync_fork_request(&self, peers: Vec<PeerId>, hash: <Block as BlockT>::Hash, number: NumberFor<Block>) {
+		self.network.service().set_sync_fork_request(peers, hash, number);
+	}
+
+	/// Add blocks to the peer -- edit the block before adding
+	pub fn generate_blocks<F>(&mut self, count: usize, origin: BlockOrigin, edit_block: F) -> H256
+		where F: FnMut(BlockBuilder<Block, PeersFullClient, polkadot_test_runtime_client::Backend>) -> Block
+	{
+		let best_hash = self.client.info().best_hash;
+		self.generate_blocks_at(BlockId::Hash(best_hash), count, origin, edit_block, false)
+	}
+
+	/// Add blocks to the peer -- edit the block before adding. The chain will
+	/// start at the given block iD.
+	fn generate_blocks_at<F>(
+		&mut self,
+		at: BlockId<Block>,
+		count: usize,
+		origin: BlockOrigin,
+		mut edit_block: F,
+		headers_only: bool,
+	) -> H256 where F: FnMut(BlockBuilder<Block, PeersFullClient, polkadot_test_runtime_client::Backend>) -> Block {
+		let full_client = self.client.as_full()
+			.expect("blocks could only be generated by full clients");
+		let mut at = full_client.header(&at).unwrap().unwrap().hash();
+		for _  in 0..count {
+			let builder = full_client.new_block_at(
+				&BlockId::Hash(at),
+				Default::default(),
+				false,
+			).unwrap();
+			let block = edit_block(builder);
+			let hash = block.header.hash();
+			trace!(
+				target: "test_network",
+				"Generating {}, (#{}, parent={})",
+				hash,
+				block.header.number,
+				block.header.parent_hash,
+			);
+			let header = block.header.clone();
+			let (import_block, cache) = self.verifier.verify(
+				origin,
+				header.clone(),
+				None,
+				if headers_only { None } else { Some(block.extrinsics) },
+			).unwrap();
+			let cache = if let Some(cache) = cache {
+				cache.into_iter().collect()
+			} else {
+				Default::default()
+			};
+			self.block_import.import_block(import_block, cache).expect("block_import failed");
+			self.network.on_block_imported(header, Vec::new(), true);
+			at = hash;
+		}
+
+		self.network.service().announce_block(at.clone(), Vec::new());
+		at
+	}
+
+	/// Push blocks to the peer (simplified: with or without a TX)
+	pub fn push_blocks(&mut self, count: usize, with_tx: bool) -> H256 {
+		let best_hash = self.client.info().best_hash;
+		self.push_blocks_at(BlockId::Hash(best_hash), count, with_tx)
+	}
+
+	/// Push blocks to the peer (simplified: with or without a TX)
+	pub fn push_headers(&mut self, count: usize) -> H256 {
+		let best_hash = self.client.info().best_hash;
+		self.generate_tx_blocks_at(BlockId::Hash(best_hash), count, false, true)
+	}
+
+	/// Push blocks to the peer (simplified: with or without a TX) starting from
+	/// given hash.
+	pub fn push_blocks_at(&mut self, at: BlockId<Block>, count: usize, with_tx: bool) -> H256 {
+		self.generate_tx_blocks_at(at, count, with_tx, false)
+	}
+
+	/// Push blocks/headers to the peer (simplified: with or without a TX) starting from
+	/// given hash.
+	fn generate_tx_blocks_at(&mut self, at: BlockId<Block>, count: usize, with_tx: bool, headers_only:bool) -> H256 {
+		if with_tx {
+			self.generate_blocks_at(
+				at,
+				count,
+				BlockOrigin::File,
+				|builder| builder.build().unwrap().block,
+				headers_only
+			)
+		} else {
+			self.generate_blocks_at(
+				at,
+				count,
+				BlockOrigin::File,
+				|builder| builder.build().unwrap().block,
+				headers_only,
+			)
+		}
+	}
+
+	/// Get a reference to the client.
+	pub fn client(&self) -> &PeersClient {
+		&self.client
+	}
+
+	/// Get a reference to the network service.
+	pub fn network_service(&self) -> &Arc<NetworkService<Block, <Block as BlockT>::Hash>> {
+		&self.network.service()
+	}
+
+	/// Test helper to compare the blockchain state of multiple (networked)
+	/// clients.
+	/// Potentially costly, as it creates in-memory copies of both blockchains in order
+	/// to compare them. If you have easier/softer checks that are sufficient, e.g.
+	/// by using .info(), you should probably use it instead of this.
+	pub fn blockchain_canon_equals(&self, other: &Self) -> bool {
+		if let (Some(mine), Some(others)) = (self.backend.clone(), other.backend.clone()) {
+			mine.as_in_memory().blockchain()
+				.canon_equals_to(others.as_in_memory().blockchain())
+		} else {
+			false
+		}
+	}
+
+	/// Count the total number of imported blocks.
+	pub fn blocks_count(&self) -> u64 {
+		self.backend.as_ref().map(
+			|backend| backend.blocks_count()
+		).unwrap_or(0)
+	}
+
+	/// Return a collection of block hashes that failed verification
+	pub fn failed_verifications(&self) -> HashMap<<Block as BlockT>::Hash, String> {
+		self.verifier.failed_verifications.lock().clone()
+	}
+}
+
+pub struct EmptyTransactionPool;
+
+impl TransactionPool<Hash, Block> for EmptyTransactionPool {
+	fn transactions(&self) -> Vec<(Hash, Extrinsic)> {
+		Vec::new()
+	}
+
+	fn hash_of(&self, _transaction: &Extrinsic) -> Hash {
+		Hash::default()
+	}
+
+	fn import(
+		&self,
+		_report_handle: ReportHandle,
+		_who: PeerId,
+		_rep_change_good: sc_network::ReputationChange,
+		_rep_change_bad: sc_network::ReputationChange,
+		_transaction: Extrinsic
+	) {}
+
+	fn on_broadcasted(&self, _: HashMap<Hash, Vec<String>>) {}
+
+	fn transaction(&self, _h: &Hash) -> Option<Extrinsic> { None }
+}
+
+/// Implements `BlockImport` for any `Transaction`. Internally the transaction is
+/// "converted", aka the field is set to `None`.
+///
+/// This is required as the `TestNetFactory` trait does not distinguish between
+/// full and light nodes.
+pub enum BlockImportAdapter<Transaction> {
+	Full(
+		Arc<Mutex<dyn BlockImport<
+			Block,
+			Transaction = TransactionFor<polkadot_test_runtime_client::Backend, Block>,
+			Error = ConsensusError
+		> + Send>>,
+		PhantomData<Transaction>,
+	),
+	Light(
+		Arc<Mutex<dyn BlockImport<
+			Block,
+			Transaction = TransactionFor<polkadot_test_runtime_client::LightBackend, Block>,
+			Error = ConsensusError
+		> + Send>>,
+		PhantomData<Transaction>,
+	),
+}
+
+impl<Transaction> BlockImportAdapter<Transaction> {
+	/// Create a new instance of `Self::Full`.
+	pub fn new_full(
+		full: impl BlockImport<
+			Block,
+			Transaction = TransactionFor<polkadot_test_runtime_client::Backend, Block>,
+			Error = ConsensusError
+		>
+		+ 'static
+		+ Send
+	) -> Self {
+		Self::Full(Arc::new(Mutex::new(full)), PhantomData)
+	}
+
+	/// Create a new instance of `Self::Light`.
+	pub fn new_light(
+		light: impl BlockImport<
+			Block,
+			Transaction = TransactionFor<polkadot_test_runtime_client::LightBackend, Block>,
+			Error = ConsensusError
+		>
+		+ 'static
+		+ Send
+	) -> Self {
+		Self::Light(Arc::new(Mutex::new(light)), PhantomData)
+	}
+}
+
+impl<Transaction> Clone for BlockImportAdapter<Transaction> {
+	fn clone(&self) -> Self {
+		match self {
+			Self::Full(full, _) => Self::Full(full.clone(), PhantomData),
+			Self::Light(light, _) => Self::Light(light.clone(), PhantomData),
+		}
+	}
+}
+
+impl<Transaction> BlockImport<Block> for BlockImportAdapter<Transaction> {
+	type Error = ConsensusError;
+	type Transaction = Transaction;
+
+	fn check_block(
+		&mut self,
+		block: BlockCheckParams<Block>,
+	) -> Result<ImportResult, Self::Error> {
+		match self {
+			Self::Full(full, _) => full.lock().check_block(block),
+			Self::Light(light, _) => light.lock().check_block(block),
+		}
+	}
+
+	fn import_block(
+		&mut self,
+		block: BlockImportParams<Block, Transaction>,
+		cache: HashMap<well_known_cache_keys::Id, Vec<u8>>,
+	) -> Result<ImportResult, Self::Error> {
+		match self {
+			Self::Full(full, _) => full.lock().import_block(block.convert_transaction(), cache),
+			Self::Light(light, _) => light.lock().import_block(block.convert_transaction(), cache),
+		}
+	}
+}
+
+/// Implements `Verifier` on an `Arc<Mutex<impl Verifier>>`. Used internally.
+#[derive(Clone)]
+struct VerifierAdapter<B: BlockT> {
+	verifier: Arc<Mutex<Box<dyn Verifier<B>>>>,
+	failed_verifications: Arc<Mutex<HashMap<B::Hash, String>>>,
+}
+
+impl<B: BlockT> Verifier<B> for VerifierAdapter<B> {
+	fn verify(
+		&mut self,
+		origin: BlockOrigin,
+		header: B::Header,
+		justification: Option<Justification>,
+		body: Option<Vec<B::Extrinsic>>
+	) -> Result<(BlockImportParams<B, ()>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
+		let hash = header.hash();
+		self.verifier.lock().verify(origin, header, justification, body).map_err(|e| {
+			self.failed_verifications.lock().insert(hash, e.clone());
+			e
+		})
+	}
+}
+
+impl<B: BlockT> VerifierAdapter<B> {
+	fn new(verifier: Arc<Mutex<Box<dyn Verifier<B>>>>) -> VerifierAdapter<B> {
+		VerifierAdapter {
+			verifier,
+			failed_verifications: Default::default(),
+		}
+	}
+}
+
+pub trait TestNetFactory: Sized {
+	type Verifier: 'static + Verifier<Block>;
+	type PeerData: Default;
+
+	/// These two need to be implemented!
+	fn from_config(config: &ProtocolConfig) -> Self;
+	fn make_verifier(
+		&self,
+		client: PeersClient,
+		config: &ProtocolConfig,
+		peer_data: &Self::PeerData,
+	) -> Self::Verifier;
+
+	/// Get reference to peer.
+	fn peer(&mut self, i: usize) -> &mut Peer<Self::PeerData>;
+	fn peers(&self) -> &Vec<Peer<Self::PeerData>>;
+	fn mut_peers<F: FnOnce(&mut Vec<Peer<Self::PeerData>>)>(
+		&mut self,
+		closure: F,
+	);
+
+	/// Get custom block import handle for fresh client, along with peer data.
+	fn make_block_import<Transaction>(&self, client: PeersClient)
+		-> (
+			BlockImportAdapter<Transaction>,
+			Option<BoxJustificationImport<Block>>,
+			Option<BoxFinalityProofImport<Block>>,
+			Option<BoxFinalityProofRequestBuilder<Block>>,
+			Self::PeerData,
+		)
+	{
+		(client.as_block_import(), None, None, None, Default::default())
+	}
+
+	/// Get finality proof provider (if supported).
+	fn make_finality_proof_provider(
+		&self,
+		_client: PeersClient,
+	) -> Option<Arc<dyn FinalityProofProvider<Block>>> {
+		None
+	}
+
+	fn default_config() -> ProtocolConfig {
+		ProtocolConfig::default()
+	}
+
+	/// Create new test network with this many peers.
+	fn new(n: usize) -> Self {
+		trace!(target: "test_network", "Creating test network");
+		let config = Self::default_config();
+		let mut net = Self::from_config(&config);
+
+		for i in 0..n {
+			trace!(target: "test_network", "Adding peer {}", i);
+			net.add_full_peer(&config);
+		}
+		net
+	}
+
+	fn add_full_peer(&mut self, config: &ProtocolConfig) {
+		self.add_full_peer_with_states(config, None)
+	}
+
+	/// Add a full peer.
+	fn add_full_peer_with_states(&mut self, config: &ProtocolConfig, keep_blocks: Option<u32>) {
+		let test_client_builder = match keep_blocks {
+			Some(keep_blocks) => TestClientBuilder::with_pruning_window(keep_blocks),
+			None => TestClientBuilder::with_default_backend(),
+		};
+		let backend = test_client_builder.backend();
+		let (c, longest_chain) = test_client_builder.build_with_longest_chain();
+		let client = Arc::new(c);
+
+		let (
+			block_import,
+			justification_import,
+			finality_proof_import,
+			finality_proof_request_builder,
+			data,
+		) = self.make_block_import(PeersClient::Full(client.clone(), backend.clone()));
+
+		let verifier = self.make_verifier(
+			PeersClient::Full(client.clone(), backend.clone()),
+			config,
+			&data,
+		);
+		let verifier = VerifierAdapter::new(Arc::new(Mutex::new(Box::new(verifier) as Box<_>)));
+
+		let import_queue = Box::new(BasicQueue::new(
+			verifier.clone(),
+			Box::new(block_import.clone()),
+			justification_import,
+			finality_proof_import,
+		));
+
+		let listen_addr = build_multiaddr![Memory(rand::random::<u64>())];
+
+		let network = NetworkWorker::new(sc_network::config::Params {
+			roles: config.roles,
+			executor: None,
+			network_config: NetworkConfiguration {
+				listen_addresses: vec![listen_addr.clone()],
+				transport: TransportConfig::MemoryOnly,
+				..NetworkConfiguration::default()
+			},
+			chain: client.clone(),
+			finality_proof_provider: self.make_finality_proof_provider(
+				PeersClient::Full(client.clone(), backend.clone()),
+			),
+			finality_proof_request_builder,
+			on_demand: None,
+			transaction_pool: Arc::new(EmptyTransactionPool),
+			protocol_id: ProtocolId::from(&b"test-protocol-name"[..]),
+			import_queue,
+			block_announce_validator: Box::new(DefaultBlockAnnounceValidator::new(client.clone())),
+			metrics_registry: None,
+		}).unwrap();
+
+		self.mut_peers(|peers| {
+			for peer in peers.iter_mut() {
+				peer.network.add_known_address(network.service().local_peer_id(), listen_addr.clone());
+			}
+
+			let imported_blocks_stream = Box::pin(client.import_notification_stream().fuse());
+			let finality_notification_stream = Box::pin(client.finality_notification_stream().fuse());
+
+			peers.push(Peer {
+				data,
+				client: PeersClient::Full(client, backend.clone()),
+				select_chain: Some(longest_chain),
+				backend: Some(backend),
+				imported_blocks_stream,
+				finality_notification_stream,
+				block_import,
+				verifier,
+				network,
+			});
+		});
+	}
+
+	/// Add a light peer.
+	fn add_light_peer(&mut self, config: &ProtocolConfig) {
+		let mut config = config.clone();
+		config.roles = Roles::LIGHT;
+
+		let (c, backend) = polkadot_test_runtime_client::new_light();
+		let client = Arc::new(c);
+		let (
+			block_import,
+			justification_import,
+			finality_proof_import,
+			finality_proof_request_builder,
+			data,
+		) = self.make_block_import(PeersClient::Light(client.clone(), backend.clone()));
+
+		let verifier = self.make_verifier(
+			PeersClient::Light(client.clone(), backend.clone()),
+			&config,
+			&data,
+		);
+		let verifier = VerifierAdapter::new(Arc::new(Mutex::new(Box::new(verifier) as Box<_>)));
+
+		let import_queue = Box::new(BasicQueue::new(
+			verifier.clone(),
+			Box::new(block_import.clone()),
+			justification_import,
+			finality_proof_import,
+		));
+
+		let listen_addr = build_multiaddr![Memory(rand::random::<u64>())];
+
+		let network = NetworkWorker::new(sc_network::config::Params {
+			roles: config.roles,
+			executor: None,
+			network_config: NetworkConfiguration {
+				listen_addresses: vec![listen_addr.clone()],
+				transport: TransportConfig::MemoryOnly,
+				..NetworkConfiguration::default()
+			},
+			chain: client.clone(),
+			finality_proof_provider: self.make_finality_proof_provider(
+				PeersClient::Light(client.clone(), backend.clone())
+			),
+			finality_proof_request_builder,
+			on_demand: None,
+			transaction_pool: Arc::new(EmptyTransactionPool),
+			protocol_id: ProtocolId::from(&b"test-protocol-name"[..]),
+			import_queue,
+			block_announce_validator: Box::new(DefaultBlockAnnounceValidator::new(client.clone())),
+			metrics_registry: None,
+		}).unwrap();
+
+		self.mut_peers(|peers| {
+			for peer in peers.iter_mut() {
+				peer.network.add_known_address(network.service().local_peer_id(), listen_addr.clone());
+			}
+
+			let imported_blocks_stream = Box::pin(client.import_notification_stream().fuse());
+			let finality_notification_stream = Box::pin(client.finality_notification_stream().fuse());
+
+			peers.push(Peer {
+				data,
+				verifier,
+				select_chain: None,
+				backend: None,
+				block_import,
+				client: PeersClient::Light(client, backend),
+				imported_blocks_stream,
+				finality_notification_stream,
+				network,
+			});
+		});
+	}
+
+	/// Polls the testnet until all nodes are in sync.
+	///
+	/// Must be executed in a task context.
+	fn poll_until_sync(&mut self, cx: &mut FutureContext) -> Poll<()> {
+		self.poll(cx);
+
+		// Return `NotReady` if there's a mismatch in the highest block number.
+		let mut highest = None;
+		for peer in self.peers().iter() {
+			if peer.is_major_syncing() || peer.network.num_queued_blocks() != 0 {
+				return Poll::Pending
+			}
+			if peer.network.num_sync_requests() != 0 {
+				return Poll::Pending
+			}
+			match (highest, peer.client.info().best_hash) {
+				(None, b) => highest = Some(b),
+				(Some(ref a), ref b) if a == b => {},
+				(Some(_), _) => return Poll::Pending
+			}
+		}
+		Poll::Ready(())
+	}
+
+	/// Polls the testnet until theres' no activiy of any kind.
+	///
+	/// Must be executed in a task context.
+	fn poll_until_idle(&mut self, cx: &mut FutureContext) -> Poll<()> {
+		self.poll(cx);
+
+		for peer in self.peers().iter() {
+			if peer.is_major_syncing() || peer.network.num_queued_blocks() != 0 {
+				return Poll::Pending
+			}
+			if peer.network.num_sync_requests() != 0 {
+				return Poll::Pending
+			}
+		}
+		Poll::Ready(())
+	}
+
+	/// Blocks the current thread until we are sync'ed.
+	///
+	/// Calls `poll_until_sync` repeatedly.
+	fn block_until_sync(&mut self) {
+		futures::executor::block_on(futures::future::poll_fn::<(), _>(|cx| self.poll_until_sync(cx)));
+	}
+
+	/// Blocks the current thread until there are no pending packets.
+	///
+	/// Calls `poll_until_idle` repeatedly with the runtime passed as parameter.
+	fn block_until_idle(&mut self) {
+		futures::executor::block_on(futures::future::poll_fn::<(), _>(|cx| self.poll_until_idle(cx)));
+	}
+
+	/// Polls the testnet. Processes all the pending actions and returns `NotReady`.
+	fn poll(&mut self, cx: &mut FutureContext) {
+		self.mut_peers(|peers| {
+			for peer in peers {
+				trace!(target: "sync", "-- Polling {}", peer.id());
+				if let Poll::Ready(res) = Pin::new(&mut peer.network).poll(cx) {
+					res.unwrap();
+				}
+				trace!(target: "sync", "-- Polling complete {}", peer.id());
+
+				// We poll `imported_blocks_stream`.
+				while let Poll::Ready(Some(notification)) = peer.imported_blocks_stream.as_mut().poll_next(cx) {
+					peer.network.on_block_imported(
+						notification.header,
+						Vec::new(),
+						true,
+					);
+				}
+
+				// We poll `finality_notification_stream`, but we only take the last event.
+				let mut last = None;
+				while let Poll::Ready(Some(item)) = peer.finality_notification_stream.as_mut().poll_next(cx) {
+					last = Some(item);
+				}
+				if let Some(notification) = last {
+					peer.network.on_block_finalized(notification.hash, notification.header);
+				}
+			}
+		});
+	}
+}
+
+pub struct TestNet {
+	peers: Vec<Peer<()>>,
+}
+
+impl TestNetFactory for TestNet {
+	type Verifier = PassThroughVerifier;
+	type PeerData = ();
+
+	/// Create new test network with peers and given config.
+	fn from_config(_config: &ProtocolConfig) -> Self {
+		TestNet {
+			peers: Vec::new(),
+		}
+	}
+
+	fn make_verifier(&self, _client: PeersClient, _config: &ProtocolConfig, _peer_data: &())
+		-> Self::Verifier
+	{
+		PassThroughVerifier(false)
+	}
+
+	fn peer(&mut self, i: usize) -> &mut Peer<()> {
+		&mut self.peers[i]
+	}
+
+	fn peers(&self) -> &Vec<Peer<()>> {
+		&self.peers
+	}
+
+	fn mut_peers<F: FnOnce(&mut Vec<Peer<()>>)>(&mut self, closure: F) {
+		closure(&mut self.peers);
+	}
+}
+
+pub struct ForceFinalized(PeersClient);
+
+impl JustificationImport<Block> for ForceFinalized {
+	type Error = ConsensusError;
+
+	fn import_justification(
+		&mut self,
+		hash: H256,
+		_number: NumberFor<Block>,
+		justification: Justification,
+	) -> Result<(), Self::Error> {
+		self.0.finalize_block(BlockId::Hash(hash), Some(justification), true)
+			.map_err(|_| ConsensusError::InvalidJustification.into())
+	}
+}
+
+pub struct JustificationTestNet(TestNet);
+
+impl TestNetFactory for JustificationTestNet {
+	type Verifier = PassThroughVerifier;
+	type PeerData = ();
+
+	fn from_config(config: &ProtocolConfig) -> Self {
+		JustificationTestNet(TestNet::from_config(config))
+	}
+
+	fn make_verifier(&self, client: PeersClient, config: &ProtocolConfig, peer_data: &()) -> Self::Verifier {
+		self.0.make_verifier(client, config, peer_data)
+	}
+
+	fn peer(&mut self, i: usize) -> &mut Peer<Self::PeerData> {
+		self.0.peer(i)
+	}
+
+	fn peers(&self) -> &Vec<Peer<Self::PeerData>> {
+		self.0.peers()
+	}
+
+	fn mut_peers<F: FnOnce(
+		&mut Vec<Peer<Self::PeerData>>,
+	)>(&mut self, closure: F) {
+		self.0.mut_peers(closure)
+	}
+
+	fn make_block_import<Transaction>(&self, client: PeersClient)
+		-> (
+			BlockImportAdapter<Transaction>,
+			Option<BoxJustificationImport<Block>>,
+			Option<BoxFinalityProofImport<Block>>,
+			Option<BoxFinalityProofRequestBuilder<Block>>,
+			Self::PeerData,
+		)
+	{
+		(
+			client.as_block_import(),
+			Some(Box::new(ForceFinalized(client))),
+			None,
+			None,
+			Default::default(),
+		)
+	}
+}