Tests

primitives/src/evm.rs

@@ -188,7 +188,7 @@ where
 
     fn pay_priority_fee(tip: Self::LiquidityInfo) {
         if let Some(tip) = tip {
-            OUT::on_unbalanceds(sp_std::vec![tip].into_iter());
+            OUT::on_unbalanceds(Some(tip).into_iter());
         }
     }
 }

runtime/astar/src/lib.rs

@@ -841,6 +841,10 @@ impl OnUnbalanced<Credit<AccountId, Balances>> for DealWithFees {
             <CollatorRewardPot as OnUnbalanced<_>>::on_unbalanced(collator);
         }
     }
+
+    fn on_unbalanced(amount: Credit<AccountId, Balances>) {
+        Self::on_unbalanceds(Some(amount).into_iter());
+    }
 }
 
 impl pallet_transaction_payment::Config for Runtime {

runtime/shibuya/src/lib.rs

@@ -837,6 +837,10 @@ impl OnUnbalanced<Credit<AccountId, Balances>> for DealWithFees {
             <CollatorRewardPot as OnUnbalanced<_>>::on_unbalanced(collator);
         }
     }
+
+    fn on_unbalanced(amount: Credit<AccountId, Balances>) {
+        Self::on_unbalanceds(Some(amount).into_iter());
+    }
 }
 
 impl pallet_transaction_payment::Config for Runtime {

runtime/shiden/src/lib.rs

@@ -816,6 +816,10 @@ impl OnUnbalanced<Credit<AccountId, Balances>> for DealWithFees {
             <CollatorRewardPot as OnUnbalanced<_>>::on_unbalanced(collator);
         }
     }
+
+    fn on_unbalanced(amount: Credit<AccountId, Balances>) {
+        Self::on_unbalanceds(Some(amount).into_iter());
+    }
 }
 
 impl pallet_transaction_payment::Config for Runtime {

tests/integration/src/fees.rs

@@ -0,0 +1,86 @@
+// This file is part of Astar.
+
+// Copyright (C) Stake Technologies Pte.Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+// Astar 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.
+
+// Astar 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 Astar. If not, see <http://www.gnu.org/licenses/>.
+
+use crate::setup::*;
+
+use frame_support::traits::Currency;
+use pallet_evm::{AddressMapping, OnChargeEVMTransaction};
+use sp_core::{H160, U256};
+use sp_runtime::traits::AccountIdConversion;
+
+#[test]
+fn evm_fees_work() {
+    new_test_ext().execute_with(|| {
+        let address = H160::repeat_byte(0xbe);
+        let mapped_address =
+            <Runtime as pallet_evm::Config>::AddressMapping::into_account_id(address);
+        Balances::make_free_balance_be(&mapped_address, 1_000_000_000_000_000);
+
+        type EvmFeeHandler = <Runtime as pallet_evm::Config>::OnChargeTransaction;
+
+        // 0. Define init values
+        let (base_fee, tip, init_fee) = (500, 100, 1000);
+        let corrected_fee = base_fee + tip;
+
+        let pot_account = PotId::get().into_account_truncating();
+        let init_reward_pot = Balances::free_balance(&pot_account);
+        let init_total_issuance = Balances::total_issuance();
+
+        // 1. Withdraw some init fee
+        let result = <EvmFeeHandler as OnChargeEVMTransaction<Runtime>>::withdraw_fee(
+            &address,
+            U256::from(init_fee),
+        );
+        let already_withdrawn = result.expect("Account is funded, must succeed.");
+
+        // 2. Correct the charged fee
+        let calculated_tip =
+            <EvmFeeHandler as OnChargeEVMTransaction<Runtime>>::correct_and_deposit_fee(
+                &address,
+                U256::from(corrected_fee),
+                U256::from(base_fee),
+                already_withdrawn,
+            );
+        assert!(calculated_tip.is_some());
+
+        // The expectation is that 20% of the fee was deposited into the reward pot, and the rest was burned.
+        assert_eq!(
+            init_reward_pot + base_fee / 5,
+            Balances::free_balance(&pot_account)
+        );
+        assert_eq!(
+            init_total_issuance - base_fee / 5 * 4,
+            Balances::total_issuance()
+        );
+
+        // 3. Deposit the tip
+        let issuance = Balances::total_issuance();
+        let pot = Balances::free_balance(&pot_account);
+        <EvmFeeHandler as OnChargeEVMTransaction<Runtime>>::pay_priority_fee(calculated_tip);
+        assert_eq!(
+            issuance,
+            Balances::total_issuance(),
+            "Total issuance should not change since tip isn't burned."
+        );
+        assert_eq!(
+            pot + tip,
+            Balances::free_balance(&pot_account),
+            "Pot should increase by the tip amount."
+        );
+    })
+}

tests/integration/src/lib.rs

@@ -52,3 +52,6 @@ mod governance;
 
 #[cfg(any(feature = "shibuya", feature = "shiden", feature = "astar"))]
 mod xcm_api;
+
+#[cfg(any(feature = "shibuya", feature = "shiden", feature = "astar"))]
+mod fees;