Add used_gas to receipts. (#139)

* Add gas_used to receipts.

* Add gas_used test.

frame/ethereum/src/lib.rs

@@ -261,7 +261,7 @@ impl<T: Trait> Module<T> {
 				)
 			),
 			gas_limit: U256::zero(), // TODO: set this using Ethereum's gas limit change algorithm.
-			gas_used: U256::zero(), // TODO: get this from receipts.
+			gas_used: receipts.clone().into_iter().fold(U256::zero(), |acc, r| acc + r.used_gas),
 			timestamp: UniqueSaturatedInto::<u64>::unique_saturated_into(
 				pallet_timestamp::Module::<T>::get()
 			),
@@ -335,9 +335,9 @@ impl<T: Trait> Module<T> {
 		);
 		let transaction_index = Pending::get().len() as u32;
 
-		let status = match transaction.action {
+		let (status, gas_used) = match transaction.action {
 			ethereum::TransactionAction::Call(target) => {
-				Self::handle_exec(
+				let (_, _, gas_used) = Self::handle_exec(
 					pallet_evm::Module::<T>::execute_call(
 						source,
 						target,
@@ -350,18 +350,18 @@ impl<T: Trait> Module<T> {
 					)?
 				)?;
 
-				TransactionStatus {
+				(TransactionStatus {
 					transaction_hash,
 					transaction_index,
 					from: source,
 					to: Some(target),
 					contract_address: None,
 					logs: Vec::new(), // TODO: feed in logs.
 					logs_bloom: Bloom::default(), // TODO: feed in bloom.
-				}
+				}, gas_used)
 			},
 			ethereum::TransactionAction::Create => {
-				let contract_address = Self::handle_exec(
+				let (_, contract_address, gas_used) = Self::handle_exec(
 					pallet_evm::Module::<T>::execute_create(
 						source,
 						transaction.input.clone(),
@@ -371,23 +371,23 @@ impl<T: Trait> Module<T> {
 						Some(transaction.nonce),
 						true,
 					)?
-				)?.1;
+				)?;
 
-				TransactionStatus {
+				(TransactionStatus {
 					transaction_hash,
 					transaction_index,
 					from: source,
 					to: None,
 					contract_address: Some(contract_address),
 					logs: Vec::new(), // TODO: feed in logs.
 					logs_bloom: Bloom::default(), // TODO: feed in bloom.
-				}
+				}, gas_used)
 			},
 		};
 
 		let receipt = ethereum::Receipt {
 			state_root: H256::default(), // TODO: should be okay / error status.
-			used_gas: U256::default(), // TODO: set this.
+			used_gas: gas_used,
 			logs_bloom: Bloom::default(), // TODO: set this.
 			logs: Vec::new(), // TODO: set this.
 		};

frame/ethereum/src/tests.rs

@@ -187,7 +187,6 @@ fn invalid_signature_should_be_ignored() {
 	});
 }
 
-
 #[test]
 fn contract_should_be_created_at_given_address() {
 	let (pairs, mut ext) = new_test_ext(1);
@@ -203,3 +202,19 @@ fn contract_should_be_created_at_given_address() {
 		assert_ne!(Evm::account_codes(erc20_address).len(), 0);
 	});
 }
+
+#[test]
+fn transaction_should_generate_correct_gas_used() {
+	let (pairs, mut ext) = new_test_ext(1);
+	let alice = &pairs[0];
+
+	let expected_gas = U256::from(891328);
+
+	ext.execute_with(|| {
+		assert_ok!(Ethereum::execute(
+			alice.address,
+			default_erc20_creation_transaction(alice),
+		));
+		assert_eq!(Pending::get()[0].2.used_gas, expected_gas);
+	});
+}