[stable2503] Backport #7952 (#8082)

Backport #7952 into `stable2503` from raymondkfcheung.

See the
[documentation](https://github.com/paritytech/polkadot-sdk/blob/master/docs/BACKPORT.md)
on how to use this bot.

<!--
  # To be used by other automation, do not modify:
  original-pr-number: #${pull_number}
-->

---------

Co-authored-by: Raymond Cheung <[email protected]>

Author: paritytech-release-backport-bot[bot]

cumulus/parachains/integration-tests/emulated/tests/assets/asset-hub-westend/src/tests/exchange_asset.rs

@@ -0,0 +1,140 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use crate::{
+	create_pool_with_wnd_on,
+	imports::{
+		asset_hub_westend_runtime::{ExistentialDeposit, Runtime},
+		*,
+	},
+};
+use asset_hub_westend_runtime::{
+	xcm_config::WestendLocation, Balances, ForeignAssets, PolkadotXcm, RuntimeOrigin,
+};
+use emulated_integration_tests_common::{accounts::ALICE, xcm_emulator::TestExt};
+use frame_support::{
+	assert_err_ignore_postinfo, assert_ok,
+	traits::fungible::{Inspect, Mutate},
+};
+use parachains_common::{AccountId, Balance};
+use sp_tracing::capture_test_logs;
+use std::convert::Into;
+use xcm::latest::{Assets, Location, Xcm};
+
+const UNITS: Balance = 1_000_000_000;
+
+#[test]
+fn exchange_asset_success() {
+	test_exchange_asset(true, 500 * UNITS, 665 * UNITS, true);
+}
+
+#[test]
+fn exchange_asset_insufficient_liquidity() {
+	let log_capture = capture_test_logs!({
+		test_exchange_asset(true, 1_000 * UNITS, 2_000 * UNITS, false);
+	});
+	assert!(log_capture.contains("NoDeal"));
+}
+
+#[test]
+fn exchange_asset_insufficient_balance() {
+	let log_capture = capture_test_logs!({
+		test_exchange_asset(true, 5_000 * UNITS, 1_665 * UNITS, false);
+	});
+	assert!(log_capture.contains("Funds are unavailable"));
+}
+
+#[test]
+fn exchange_asset_pool_not_created() {
+	test_exchange_asset(false, 500 * UNITS, 665 * UNITS, false);
+}
+
+fn test_exchange_asset(
+	create_pool: bool,
+	give_amount: Balance,
+	want_amount: Balance,
+	should_succeed: bool,
+) {
+	let alice: AccountId = Westend::account_id_of(ALICE);
+	let native_asset_location = WestendLocation::get();
+	let native_asset_id = AssetId(native_asset_location.clone());
+	let origin = RuntimeOrigin::signed(alice.clone());
+	let asset_location = Location::new(1, [Parachain(2001)]);
+	let asset_id = AssetId(asset_location.clone());
+
+	// Setup initial state
+	AssetHubWestend::execute_with(|| {
+		assert_ok!(<Balances as Mutate<_>>::mint_into(
+			&alice,
+			ExistentialDeposit::get() + (1_000 * UNITS)
+		));
+
+		assert_ok!(ForeignAssets::force_create(
+			RuntimeOrigin::root(),
+			asset_location.clone().into(),
+			alice.clone().into(),
+			true,
+			1
+		));
+	});
+
+	if create_pool {
+		create_pool_with_wnd_on!(AssetHubWestend, asset_location.clone(), true, alice.clone());
+	}
+
+	// Execute and verify swap
+	AssetHubWestend::execute_with(|| {
+		let foreign_balance_before = ForeignAssets::balance(asset_location.clone(), &alice);
+		let wnd_balance_before = Balances::total_balance(&alice);
+
+		let give: Assets = (native_asset_id, give_amount).into();
+		let want: Assets = (asset_id, want_amount).into();
+		let xcm = Xcm(vec![
+			WithdrawAsset(give.clone().into()),
+			ExchangeAsset { give: give.into(), want: want.into(), maximal: true },
+			DepositAsset { assets: Wild(All), beneficiary: alice.clone().into() },
+		]);
+
+		let result = PolkadotXcm::execute(origin, bx!(xcm::VersionedXcm::from(xcm)), Weight::MAX);
+
+		let foreign_balance_after = ForeignAssets::balance(asset_location, &alice);
+		let wnd_balance_after = Balances::total_balance(&alice);
+
+		if should_succeed {
+			assert_ok!(result);
+			assert!(
+				foreign_balance_after >= foreign_balance_before + want_amount,
+				"Expected foreign balance to increase by at least {want_amount} units, got {foreign_balance_after} from {foreign_balance_before}"
+			);
+			assert_eq!(
+				wnd_balance_after, wnd_balance_before - give_amount,
+				"Expected WND balance to decrease by {give_amount} units, got {wnd_balance_after} from {wnd_balance_before}"
+			);
+		} else {
+			assert_err_ignore_postinfo!(
+				result,
+				pallet_xcm::Error::<Runtime>::LocalExecutionIncomplete
+			);
+			assert_eq!(
+				foreign_balance_after, foreign_balance_before,
+				"Foreign balance changed unexpectedly: got {foreign_balance_after}, expected {foreign_balance_before}"
+			);
+			assert_eq!(
+				wnd_balance_after, wnd_balance_before,
+				"WND balance changed unexpectedly: got {wnd_balance_after}, expected {wnd_balance_before}"
+			);
+		}
+	});
+}

cumulus/parachains/integration-tests/emulated/tests/assets/asset-hub-westend/src/tests/mod.rs

@@ -14,6 +14,7 @@
 // limitations under the License.
 
 mod claim_assets;
+mod exchange_asset;
 mod fellowship_treasury;
 mod hybrid_transfers;
 mod reserve_transfer;

cumulus/parachains/runtimes/assets/asset-hub-westend/src/lib.rs

@@ -2162,7 +2162,54 @@ impl_runtime_apis! {
 				}
 
 				fn worst_case_asset_exchange() -> Result<(XcmAssets, XcmAssets), BenchmarkError> {
-					Err(BenchmarkError::Skip)
+					let native_asset_location = WestendLocation::get();
+					let native_asset_id = AssetId(native_asset_location.clone());
+					let (account, _) = pallet_xcm_benchmarks::account_and_location::<Runtime>(1);
+					let origin = RuntimeOrigin::signed(account.clone());
+					let asset_location = Location::new(1, [Parachain(2001)]);
+					let asset_id = AssetId(asset_location.clone());
+
+					assert_ok!(<Balances as fungible::Mutate<_>>::mint_into(
+						&account,
+						ExistentialDeposit::get() + (1_000 * UNITS)
+					));
+
+					assert_ok!(ForeignAssets::force_create(
+						RuntimeOrigin::root(),
+						asset_location.clone().into(),
+						account.clone().into(),
+						true,
+						1,
+					));
+
+					assert_ok!(ForeignAssets::mint(
+						origin.clone(),
+						asset_location.clone().into(),
+						account.clone().into(),
+						3_000 * UNITS,
+					));
+
+					assert_ok!(AssetConversion::create_pool(
+						origin.clone(),
+						native_asset_location.clone().into(),
+						asset_location.clone().into(),
+					));
+
+					assert_ok!(AssetConversion::add_liquidity(
+						origin,
+						native_asset_location.into(),
+						asset_location.into(),
+						1_000 * UNITS,
+						2_000 * UNITS,
+						1,
+						1,
+						account.into(),
+					));
+
+					let give_assets: XcmAssets = (native_asset_id, 500 * UNITS).into();
+					let receive_assets: XcmAssets = (asset_id, 660 * UNITS).into();
+
+					Ok((give_assets, receive_assets))
 				}
 
 				fn universal_alias() -> Result<(Location, Junction), BenchmarkError> {

cumulus/parachains/runtimes/assets/asset-hub-westend/src/weights/xcm/mod.rs

@@ -124,8 +124,11 @@ impl<Call> XcmWeightInfo<Call> for AssetHubWestendXcmWeight<Call> {
 	fn deposit_reserve_asset(assets: &AssetFilter, _dest: &Location, _xcm: &Xcm<()>) -> Weight {
 		assets.weigh_assets(XcmFungibleWeight::<Runtime>::deposit_reserve_asset())
 	}
-	fn exchange_asset(_give: &AssetFilter, _receive: &Assets, _maximal: &bool) -> Weight {
-		XcmFungibleWeight::<Runtime>::exchange_asset()
+	fn exchange_asset(give: &AssetFilter, receive: &Assets, _maximal: &bool) -> Weight {
+		let base_weight = XcmGeneric::<Runtime>::exchange_asset();
+		let give_weight = give.weigh_assets(base_weight);
+		let receive_weight = receive.weigh_assets(base_weight);
+		give_weight.max(receive_weight)
 	}
 	fn initiate_reserve_withdraw(
 		assets: &AssetFilter,