tests.rs

use asset_test_utils::{ExtBuilder, RuntimeHelper};
use frame_support::{
	assert_noop, assert_ok,
	traits::PalletInfo,
	weights::{Weight, WeightToFee as WeightToFeeT},
};
use parachains_common::{AccountId, AuraId};
pub use westmint_runtime::{
	constants::fee::WeightToFee, xcm_config::XcmConfig, Assets, Balances, ExistentialDeposit,
	Runtime, SessionKeys, System,
};
use xcm::latest::prelude::*;
use xcm_executor::traits::WeightTrader;

pub const ALICE: [u8; 32] = [1u8; 32];

#[test]
fn test_asset_xcm_trader() {
	ExtBuilder::<Runtime>::default()
		.with_collators(vec![AccountId::from(ALICE)])
		.with_session_keys(vec![(
			AccountId::from(ALICE),
			AccountId::from(ALICE),
			SessionKeys { aura: AuraId::from(sp_core::sr25519::Public::from_raw(ALICE)) },
		)])
		.build()
		.execute_with(|| {
			// We need root origin to create a sufficient asset
			// We set existential deposit to be identical to the one for Balances first
			assert_ok!(Assets::force_create(
				RuntimeHelper::<Runtime>::root_origin(),
				1,
				AccountId::from(ALICE).into(),
				true,
				ExistentialDeposit::get()
			));

			// We first mint enough asset for the account to exist for assets
			assert_ok!(Assets::mint(
				RuntimeHelper::<Runtime>::origin_of(AccountId::from(ALICE)),
				1,
				AccountId::from(ALICE).into(),
				ExistentialDeposit::get()
			));

			let mut trader = <XcmConfig as xcm_executor::Config>::Trader::new();

			// Set Alice as block author, who will receive fees
			RuntimeHelper::<Runtime>::run_to_block(2, Some(AccountId::from(ALICE)));

			// We are going to buy 4e9 weight
			let bought = 4_000_000_000u64;

			// lets calculate amount needed
			let amount_needed = WeightToFee::weight_to_fee(&Weight::from_ref_time(bought));

			let asset_multilocation = MultiLocation::new(
				0,
				X2(
					PalletInstance(
						<Runtime as frame_system::Config>::PalletInfo::index::<Assets>().unwrap()
							as u8,
					),
					GeneralIndex(1),
				),
			);

			let asset: MultiAsset = (asset_multilocation, amount_needed).into();

			// Make sure buy_weight does not return an error
			assert_ok!(trader.buy_weight(bought, asset.into()));

			// Drop trader
			drop(trader);

			// Make sure author(Alice) has received the amount
			assert_eq!(
				Assets::balance(1, AccountId::from(ALICE)),
				ExistentialDeposit::get() + amount_needed
			);

			// We also need to ensure the total supply increased
			assert_eq!(Assets::total_supply(1), ExistentialDeposit::get() + amount_needed);
		});
}

#[test]
fn test_asset_xcm_trader_with_refund() {
	ExtBuilder::<Runtime>::default()
		.with_collators(vec![AccountId::from(ALICE)])
		.with_session_keys(vec![(
			AccountId::from(ALICE),
			AccountId::from(ALICE),
			SessionKeys { aura: AuraId::from(sp_core::sr25519::Public::from_raw(ALICE)) },
		)])
		.build()
		.execute_with(|| {
			// We need root origin to create a sufficient asset
			// We set existential deposit to be identical to the one for Balances first
			assert_ok!(Assets::force_create(
				RuntimeHelper::<Runtime>::root_origin(),
				1,
				AccountId::from(ALICE).into(),
				true,
				ExistentialDeposit::get()
			));

			// We first mint enough asset for the account to exist for assets
			assert_ok!(Assets::mint(
				RuntimeHelper::<Runtime>::origin_of(AccountId::from(ALICE)),
				1,
				AccountId::from(ALICE).into(),
				ExistentialDeposit::get()
			));

			let mut trader = <XcmConfig as xcm_executor::Config>::Trader::new();

			// Set Alice as block author, who will receive fees
			RuntimeHelper::<Runtime>::run_to_block(2, Some(AccountId::from(ALICE)));

			// We are going to buy 4e9 weight
			let bought = 4_000_000_000u64;
			let asset_multilocation = MultiLocation::new(
				0,
				X2(
					PalletInstance(
						<Runtime as frame_system::Config>::PalletInfo::index::<Assets>().unwrap()
							as u8,
					),
					GeneralIndex(1),
				),
			);

			// lets calculate amount needed
			let amount_bought = WeightToFee::weight_to_fee(&Weight::from_ref_time(bought));

			let asset: MultiAsset = (asset_multilocation.clone(), amount_bought).into();

			// Make sure buy_weight does not return an error
			assert_ok!(trader.buy_weight(bought, asset.clone().into()));

			// Make sure again buy_weight does return an error
			assert_noop!(trader.buy_weight(bought, asset.into()), XcmError::NotWithdrawable);

			// We actually use half of the weight
			let weight_used = bought / 2;

			// Make sure refurnd works.
			let amount_refunded =
				WeightToFee::weight_to_fee(&Weight::from_ref_time(bought - weight_used));

			assert_eq!(
				trader.refund_weight(bought - weight_used),
				Some((asset_multilocation, amount_refunded).into())
			);

			// Drop trader
			drop(trader);

			// We only should have paid for half of the bought weight
			let fees_paid = WeightToFee::weight_to_fee(&Weight::from_ref_time(weight_used));

			assert_eq!(
				Assets::balance(1, AccountId::from(ALICE)),
				ExistentialDeposit::get() + fees_paid
			);

			// We also need to ensure the total supply increased
			assert_eq!(Assets::total_supply(1), ExistentialDeposit::get() + fees_paid);
		});
}

#[test]
fn test_asset_xcm_trader_refund_not_possible_since_amount_less_than_ed() {
	ExtBuilder::<Runtime>::default()
		.with_collators(vec![AccountId::from(ALICE)])
		.with_session_keys(vec![(
			AccountId::from(ALICE),
			AccountId::from(ALICE),
			SessionKeys { aura: AuraId::from(sp_core::sr25519::Public::from_raw(ALICE)) },
		)])
		.build()
		.execute_with(|| {
			// We need root origin to create a sufficient asset
			// We set existential deposit to be identical to the one for Balances first
			assert_ok!(Assets::force_create(
				RuntimeHelper::<Runtime>::root_origin(),
				1,
				AccountId::from(ALICE).into(),
				true,
				ExistentialDeposit::get()
			));

			let mut trader = <XcmConfig as xcm_executor::Config>::Trader::new();

			// Set Alice as block author, who will receive fees
			RuntimeHelper::<Runtime>::run_to_block(2, Some(AccountId::from(ALICE)));

			// We are going to buy 4e9 weight
			let bought = 500_000_000u64;

			let asset_multilocation = MultiLocation::new(
				0,
				X2(
					PalletInstance(
						<Runtime as frame_system::Config>::PalletInfo::index::<Assets>().unwrap()
							as u8,
					),
					GeneralIndex(1),
				),
			);

			let amount_bought = WeightToFee::weight_to_fee(&Weight::from_ref_time(bought));

			assert!(
				amount_bought < ExistentialDeposit::get(),
				"we are testing what happens when the amount does not exceed ED"
			);

			let asset: MultiAsset = (asset_multilocation.clone(), amount_bought).into();

			// Buy weight should return an error
			assert_noop!(trader.buy_weight(bought, asset.into()), XcmError::TooExpensive);

			// not credited since the ED is higher than this value
			assert_eq!(Assets::balance(1, AccountId::from(ALICE)), 0);

			// We also need to ensure the total supply did not increase
			assert_eq!(Assets::total_supply(1), 0);
		});
}

#[test]
fn test_that_buying_ed_refund_does_not_refund() {
	ExtBuilder::<Runtime>::default()
		.with_collators(vec![AccountId::from(ALICE)])
		.with_session_keys(vec![(
			AccountId::from(ALICE),
			AccountId::from(ALICE),
			SessionKeys { aura: AuraId::from(sp_core::sr25519::Public::from_raw(ALICE)) },
		)])
		.build()
		.execute_with(|| {
			// We need root origin to create a sufficient asset
			// We set existential deposit to be identical to the one for Balances first
			assert_ok!(Assets::force_create(
				RuntimeHelper::<Runtime>::root_origin(),
				1,
				AccountId::from(ALICE).into(),
				true,
				ExistentialDeposit::get()
			));

			let mut trader = <XcmConfig as xcm_executor::Config>::Trader::new();

			// Set Alice as block author, who will receive fees
			RuntimeHelper::<Runtime>::run_to_block(2, Some(AccountId::from(ALICE)));

			let bought = 500_000_000u64;

			let asset_multilocation = MultiLocation::new(
				0,
				X2(
					PalletInstance(
						<Runtime as frame_system::Config>::PalletInfo::index::<Assets>().unwrap()
							as u8,
					),
					GeneralIndex(1),
				),
			);

			let amount_bought = WeightToFee::weight_to_fee(&Weight::from_ref_time(bought));

			assert!(
				amount_bought < ExistentialDeposit::get(),
				"we are testing what happens when the amount does not exceed ED"
			);

			// We know we will have to buy at least ED, so lets make sure first it will
			// fail with a payment of less than ED
			let asset: MultiAsset = (asset_multilocation.clone(), amount_bought).into();
			assert_noop!(trader.buy_weight(bought, asset.into()), XcmError::TooExpensive);

			// Now lets buy ED at least
			let asset: MultiAsset = (asset_multilocation.clone(), ExistentialDeposit::get()).into();

			// Buy weight should work
			assert_ok!(trader.buy_weight(bought, asset.into()));

			// Should return None. We have a specific check making sure we dont go below ED for
			// drop payment
			assert_eq!(trader.refund_weight(bought), None);

			// Drop trader
			drop(trader);

			// Make sure author(Alice) has received the amount
			assert_eq!(Assets::balance(1, AccountId::from(ALICE)), ExistentialDeposit::get());

			// We also need to ensure the total supply increased
			assert_eq!(Assets::total_supply(1), ExistentialDeposit::get());
		});
}