Support westend integration tests (#2649)

* mostly there with westend

* add network

* initial way to set host api version

* 3 tests all passing

* Remove duplication

* fix runtime-benchmarks

* Fix typo

---------

Co-authored-by: joepetrowski <joe@parity.io>

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

@@ -0,0 +1,58 @@
+use crate::*;
+
+#[test]
+fn transact_sudo_from_relay_to_assets_para() {
+	// Init tests variables
+	// Call to be executed in Assets Parachain
+	const ASSET_ID: u32 = 1;
+
+	let call = <AssetHubWestend as Para>::RuntimeCall::Assets(pallet_assets::Call::<
+		<AssetHubWestend as Para>::Runtime,
+		Instance1,
+	>::force_create {
+		id: ASSET_ID.into(),
+		is_sufficient: true,
+		min_balance: 1000,
+		owner: AssetHubWestendSender::get().into(),
+	})
+	.encode()
+	.into();
+
+	// XcmPallet send arguments
+	let sudo_origin = <Westend as Relay>::RuntimeOrigin::root();
+	let assets_para_destination: VersionedMultiLocation =
+		Westend::child_location_of(AssetHubWestend::para_id()).into();
+
+	let weight_limit = WeightLimit::Unlimited;
+	let require_weight_at_most = Weight::from_parts(1000000000, 200000);
+	let origin_kind = OriginKind::Superuser;
+	let check_origin = None;
+
+	let xcm = VersionedXcm::from(Xcm(vec![
+		UnpaidExecution { weight_limit, check_origin },
+		Transact { require_weight_at_most, origin_kind, call },
+	]));
+
+	// Send XCM message from Relay Chain
+	Westend::execute_with(|| {
+		assert_ok!(<Westend as WestendPallet>::XcmPallet::send(
+			sudo_origin,
+			bx!(assets_para_destination),
+			bx!(xcm),
+		));
+
+		type RuntimeEvent = <Westend as Relay>::RuntimeEvent;
+
+		assert_expected_events!(
+			Westend,
+			vec![
+				RuntimeEvent::XcmPallet(pallet_xcm::Event::Sent { .. }) => {},
+			]
+		);
+	});
+
+	// Receive XCM message in Assets Parachain
+	AssetHubWestend::execute_with(|| {
+		assert!(<AssetHubWestend as AssetHubWestendPallet>::Assets::asset_exists(ASSET_ID));
+	});
+}