Remove eth-connector fee logic (#882)

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## Description
Remove unused and redundant `Fee` logic of the eth-connector.
The primary purpose of this change is to unify the message format for
transferring ERC20 and native base tokens.
These changes should simplify the interactions with silo contracts,
especially when the base token is an ERC20 token.

## Performance / NEAR gas cost considerations
Slight reduction in gas
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## Testing
Added unit and workspace tests
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## How should this be reviewed
Verify the `ft_on_transfer` logic for both internal and external
connectors.
This change should be backward compatible, not breaking any internal or
external components/services.
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## Additional information
N/A
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---------

Co-authored-by: Oleksandr Anyshchenko <[email protected]>

engine-tests-connector/src/connector.rs

@@ -267,6 +267,64 @@ async fn test_ft_transfer_call_eth() -> anyhow::Result<()> {
     Ok(())
 }
 
+#[tokio::test]
+async fn test_ft_transfer_call_without_fee() -> anyhow::Result<()> {
+    let contract = TestContract::new().await?;
+    contract.call_deposit_eth_to_near().await?;
+
+    let user_acc = contract
+        .create_sub_account(DEPOSITED_RECIPIENT_NAME)
+        .await?;
+    assert_eq!(
+        contract.get_eth_on_near_balance(user_acc.id()).await?.0,
+        DEPOSITED_AMOUNT,
+    );
+    assert_eq!(
+        contract
+            .get_eth_on_near_balance(contract.engine_contract.id())
+            .await?
+            .0,
+        0,
+    );
+
+    let transfer_amount: U128 = 50.into();
+    let message = RECIPIENT_ETH_ADDRESS;
+    let memo: Option<String> = None;
+    let res = user_acc
+        .call(contract.engine_contract.id(), "ft_transfer_call")
+        .args_json(json!({
+            "receiver_id": contract.engine_contract.id(),
+            "amount": transfer_amount,
+            "memo": memo,
+            "msg": message,
+        }))
+        .gas(DEFAULT_GAS)
+        .deposit(ONE_YOCTO)
+        .transact()
+        .await?;
+    assert!(res.is_success());
+
+    assert_eq!(
+        contract.get_eth_on_near_balance(user_acc.id()).await?.0,
+        DEPOSITED_AMOUNT - transfer_amount.0,
+    );
+    assert_eq!(
+        contract
+            .get_eth_on_near_balance(contract.engine_contract.id())
+            .await?
+            .0,
+        transfer_amount.0,
+    );
+    assert_eq!(
+        contract
+            .get_eth_balance(&validate_eth_address(RECIPIENT_ETH_ADDRESS),)
+            .await?,
+        transfer_amount.0,
+    );
+    assert_eq!(contract.total_supply().await?, DEPOSITED_AMOUNT);
+    Ok(())
+}
+
 #[tokio::test]
 async fn test_ft_transfer_call_without_message() -> anyhow::Result<()> {
     let contract = TestContract::new().await?;
@@ -438,8 +496,7 @@ async fn test_deposit_with_0x_prefix() -> anyhow::Result<()> {
     let message = [CONTRACT_ACC, ":", "0x", &recipient_address_encoded].concat();
     let fee: Fee = Fee::new(NEP141Wei::new(0));
     let token_message_data =
-        TokenMessageData::parse_event_message_and_prepare_token_message_data(&message, fee)
-            .unwrap();
+        TokenMessageData::parse_event_message_and_prepare_token_message_data(&message).unwrap();
 
     let deposit_event = DepositedEvent {
         eth_custodian_address,

engine-tests/src/tests/erc20_connector.rs

@@ -1020,8 +1020,7 @@ pub mod workspace {
         let message = recipient_id.to_string();
         let fee: Fee = Fee::new(NEP141Wei::new(0));
         let token_message_data =
-            TokenMessageData::parse_event_message_and_prepare_token_message_data(&message, fee)
-                .unwrap();
+            TokenMessageData::parse_event_message_and_prepare_token_message_data(&message).unwrap();
 
         let deposit_event = DepositedEvent {
             eth_custodian_address,

engine-tests/src/tests/standalone/sync.rs

@@ -472,8 +472,7 @@ fn mock_proof(recipient_address: Address, deposit_amount: Wei) -> aurora_engine:
     let fee = Fee::new(NEP141Wei::new(0));
     let message = ["aurora", ":", recipient_address.encode().as_str()].concat();
     let token_message_data: TokenMessageData =
-        TokenMessageData::parse_event_message_and_prepare_token_message_data(&message, fee)
-            .unwrap();
+        TokenMessageData::parse_event_message_and_prepare_token_message_data(&message).unwrap();
 
     let deposit_event = DepositedEvent {
         eth_custodian_address,

engine-tests/src/utils/standalone/mocks/mod.rs

@@ -3,8 +3,6 @@ use aurora_engine::engine;
 use aurora_engine::engine::Engine;
 #[cfg(not(feature = "ext-connector"))]
 use aurora_engine::parameters::InitCallArgs;
-#[cfg(not(feature = "ext-connector"))]
-use aurora_engine_modexp::ModExpAlgorithm;
 use aurora_engine_sdk::env::{Env, DEFAULT_PREPAID_GAS};
 use aurora_engine_sdk::io::IO;
 #[cfg(not(feature = "ext-connector"))]
@@ -114,19 +112,13 @@ pub fn mint_evm_account<I: IO + Copy, E: Env>(
     };
 
     #[cfg(not(feature = "ext-connector"))]
-    deposit(io, &engine, &env.current_account_id(), address, balance);
+    deposit(io, &env.current_account_id(), address, balance);
 
     engine.apply(std::iter::once(state_change), std::iter::empty(), false);
 }
 
 #[cfg(not(feature = "ext-connector"))]
-fn deposit<I: IO + Copy, E: Env, M: ModExpAlgorithm>(
-    mut io: I,
-    engine: &Engine<I, E, M>,
-    aurora_account_id: &AccountId,
-    address: Address,
-    balance: Wei,
-) {
+fn deposit<I: IO + Copy>(mut io: I, aurora_account_id: &AccountId, address: Address, balance: Wei) {
     const DEFAULT_GAS: u64 = 300_000_000_000_000;
     let deposit_args = aurora_engine_types::parameters::connector::FinishDepositCallArgs {
         new_owner_id: aurora_account_id.clone(),
@@ -165,7 +157,7 @@ fn deposit<I: IO + Copy, E: Env, M: ModExpAlgorithm>(
             hex::encode(address.as_bytes())
         ),
     };
-    connector.ft_on_transfer(engine, &transfer_args).unwrap();
+    connector.ft_on_transfer(&transfer_args).unwrap();
 }
 
 #[cfg(not(feature = "ext-connector"))]