add integration tests to xcm-builder

xcm/xcm-builder/Cargo.toml

@@ -21,6 +21,12 @@ pallet-transaction-payment = { git = "https://github.com/paritytech/substrate",
 # Polkadot dependencies
 polkadot-parachain = { path = "../../parachain", default-features = false }
 
+[dev-dependencies]
+pallet-balances = { git = "https://github.com/paritytech/substrate", branch = "master" }
+pallet-xcm = { path = "../pallet-xcm" }
+polkadot-runtime-parachains = { path = "../../runtime/parachains" }
+sp-core = { git = "https://github.com/paritytech/substrate", branch = "master" }
+
 [features]
 default = ["std"]
 runtime-benchmarks = []

xcm/xcm-builder/src/barriers.rs

@@ -23,6 +23,10 @@ use xcm_executor::traits::{OnResponse, ShouldExecute};
 use polkadot_parachain::primitives::IsSystem;
 
 /// Execution barrier that just takes `shallow_weight` from `weight_credit`.
+///
+/// Useful to allow XCM execution by local chain users via extrinsics.
+/// E.g. `pallet_xcm::reserve_asset_transfer` to transfer a reserve asset
+/// out of the local chain to another one.
 pub struct TakeWeightCredit;
 impl ShouldExecute for TakeWeightCredit {
 	fn should_execute<Call>(
@@ -39,6 +43,8 @@ impl ShouldExecute for TakeWeightCredit {
 
 /// Allows execution from `origin` if it is contained in `T` (i.e. `T::Contains(origin)`) taking payments into
 /// account.
+///
+/// Only allows for asset-based XCMs.
 pub struct AllowTopLevelPaidExecutionFrom<T>(PhantomData<T>);
 impl<T: Contains<MultiLocation>> ShouldExecute for AllowTopLevelPaidExecutionFrom<T> {
 	fn should_execute<Call>(

xcm/xcm-builder/src/currency_adapter.rs

@@ -58,8 +58,8 @@ impl From<Error> for XcmError {
 ///
 /// /// Our relay chain's location.
 /// parameter_types! {
-///     RelayChain: MultiLocation = MultiLocation::X1(Junction::Parent);
-///     CheckingAccount: AccountId = Default::default();
+///     pub RelayChain: MultiLocation = MultiLocation::X1(Junction::Parent);
+///     pub CheckingAccount: AccountId = Default::default();
 /// }
 ///
 /// /// Some items that implement `Convert<MultiLocation, AccountId>`. Can be more, but for now we just assume we accept

xcm/xcm-builder/src/integration_mock.rs

@@ -0,0 +1,193 @@
+// 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/>.
+
+use frame_support::{
+	construct_runtime, parameter_types,
+	traits::{All, AllowAll},
+	weights::Weight,
+};
+use sp_core::H256;
+use sp_runtime::{testing::Header, traits::IdentityLookup, AccountId32};
+
+use polkadot_parachain::primitives::Id as ParaId;
+use polkadot_runtime_parachains::{configuration, origin, shared};
+use xcm::opaque::v0::MultiAsset;
+use xcm::v0::{MultiLocation::self, NetworkId};
+use xcm_executor::XcmExecutor;
+
+use crate as xcm_builder;
+use xcm_builder::{
+	AccountId32Aliases, AllowTopLevelPaidExecutionFrom, ChildParachainAsNative,
+	ChildParachainConvertsVia, ChildSystemParachainAsSuperuser,
+	CurrencyAdapter as XcmCurrencyAdapter, FixedRateOfConcreteFungible, FixedWeightBounds,
+	IsConcrete, LocationInverter, SignedAccountId32AsNative, SignedToAccountId32,
+	SovereignSignedViaLocation, TakeWeightCredit, IsChildSystemParachain, AllowUnpaidExecutionFrom
+};
+use crate::mock;
+
+pub type AccountId = AccountId32;
+pub type Balance = u128;
+
+// copied from kusama constants
+pub const UNITS: Balance = 1_000_000_000_000;
+pub const CENTS: Balance = UNITS / 30_000;
+
+parameter_types! {
+	pub const BlockHashCount: u64 = 250;
+}
+
+impl frame_system::Config for Runtime {
+	type Origin = Origin;
+	type Call = Call;
+	type Index = u64;
+	type BlockNumber = u64;
+	type Hash = H256;
+	type Hashing = ::sp_runtime::traits::BlakeTwo256;
+	type AccountId = AccountId;
+	type Lookup = IdentityLookup<Self::AccountId>;
+	type Header = Header;
+	type Event = Event;
+	type BlockHashCount = BlockHashCount;
+	type BlockWeights = ();
+	type BlockLength = ();
+	type Version = ();
+	type PalletInfo = PalletInfo;
+	type AccountData = pallet_balances::AccountData<Balance>;
+	type OnNewAccount = ();
+	type OnKilledAccount = ();
+	type DbWeight = ();
+	type BaseCallFilter = AllowAll;
+	type SystemWeightInfo = ();
+	type SS58Prefix = ();
+	type OnSetCode = ();
+}
+
+parameter_types! {
+	pub ExistentialDeposit: Balance = 1 * CENTS;
+	pub const MaxLocks: u32 = 50;
+	pub const MaxReserves: u32 = 50;
+}
+
+impl pallet_balances::Config for Runtime {
+	type MaxLocks = MaxLocks;
+	type Balance = Balance;
+	type Event = Event;
+	type DustRemoval = ();
+	type ExistentialDeposit = ExistentialDeposit;
+	type AccountStore = System;
+	type WeightInfo = ();
+	type MaxReserves = MaxReserves;
+	type ReserveIdentifier = [u8; 8];
+}
+
+impl shared::Config for Runtime {}
+
+impl configuration::Config for Runtime {}
+
+// aims to closely emulate the Kusama XcmConfig
+parameter_types! {
+	pub const KsmLocation: MultiLocation = MultiLocation::Null;
+	pub const KusamaNetwork: NetworkId = NetworkId::Kusama;
+	pub Ancestry: MultiLocation = MultiLocation::Null;
+	pub CheckAccount: AccountId = XcmPallet::check_account();
+}
+
+pub type SovereignAccountOf =
+	(ChildParachainConvertsVia<ParaId, AccountId>, AccountId32Aliases<KusamaNetwork, AccountId>);
+
+pub type LocalAssetTransactor =
+	XcmCurrencyAdapter<Balances, IsConcrete<KsmLocation>, SovereignAccountOf, AccountId, CheckAccount>;
+
+type LocalOriginConverter = (
+	SovereignSignedViaLocation<SovereignAccountOf, Origin>,
+	ChildParachainAsNative<origin::Origin, Origin>,
+	SignedAccountId32AsNative<KusamaNetwork, Origin>,
+	ChildSystemParachainAsSuperuser<ParaId, Origin>,
+);
+
+parameter_types! {
+	pub const BaseXcmWeight: Weight = 1_000_000_000;
+	pub KsmPerSecond: (MultiLocation, u128) = (KsmLocation::get(), 1);
+}
+
+pub type Barrier = (
+	TakeWeightCredit,
+	AllowTopLevelPaidExecutionFrom<All<MultiLocation>>,
+	// Unused/Untested
+	AllowUnpaidExecutionFrom<IsChildSystemParachain<ParaId>>,
+);
+
+pub struct XcmConfig;
+impl xcm_executor::Config for XcmConfig {
+	type Call = Call;
+	type XcmSender = mock::TestSendXcm;
+	type AssetTransactor = LocalAssetTransactor;
+	type OriginConverter = LocalOriginConverter;
+	type IsReserve = ();
+	type IsTeleporter = ();
+	type LocationInverter = LocationInverter<Ancestry>;
+	type Barrier = Barrier;
+	type Weigher = FixedWeightBounds<BaseXcmWeight, Call>;
+	type Trader = FixedRateOfConcreteFungible<KsmPerSecond, ()>;
+	type ResponseHandler = ();
+}
+
+pub type LocalOriginToLocation = SignedToAccountId32<Origin, AccountId, KusamaNetwork>;
+
+impl pallet_xcm::Config for Runtime {
+	type Event = Event;
+	type SendXcmOrigin = xcm_builder::EnsureXcmOrigin<Origin, LocalOriginToLocation>;
+	type XcmRouter = mock::TestSendXcm;
+	// Anyone can execute XCM messages locally...
+	type ExecuteXcmOrigin = xcm_builder::EnsureXcmOrigin<Origin, LocalOriginToLocation>;
+	type XcmExecuteFilter = ();
+	type XcmExecutor = XcmExecutor<XcmConfig>;
+	type XcmTeleportFilter = All<(MultiLocation, Vec<MultiAsset>)>;
+	type XcmReserveTransferFilter = All<(MultiLocation, Vec<MultiAsset>)>;
+	type Weigher = FixedWeightBounds<BaseXcmWeight, Call>;
+}
+
+impl origin::Config for Runtime {}
+
+type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Runtime>;
+type Block = frame_system::mocking::MockBlock<Runtime>;
+
+construct_runtime!(
+	pub enum Runtime where
+		Block = Block,
+		NodeBlock = Block,
+		UncheckedExtrinsic = UncheckedExtrinsic,
+	{
+		System: frame_system::{Pallet, Call, Storage, Config, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		ParasOrigin: origin::{Pallet, Origin},
+		XcmPallet: pallet_xcm::{Pallet, Call, Storage, Event<T>},
+	}
+);
+
+pub fn kusama_like_with_balances(balances: Vec<(AccountId, Balance)>) -> sp_io::TestExternalities {
+	let mut t = frame_system::GenesisConfig::default().build_storage::<Runtime>().unwrap();
+
+	pallet_balances::GenesisConfig::<Runtime> {
+		balances,
+	}
+	.assimilate_storage(&mut t)
+	.unwrap();
+
+	let mut ext = sp_io::TestExternalities::new(t);
+	ext.execute_with(|| System::set_block_number(1));
+	ext
+}