Implement balance_transfer_keep_alive (#775)

* Implement functionality

* Create test for balance_transfer_keep_alive

* Incorporate review feedback

src/extrinsic/balances.rs

@@ -30,11 +30,15 @@ use codec::{Compact, Encode};
 
 pub const BALANCES_MODULE: &str = "Balances";
 pub const TRANSFER_ALLOW_DEATH: &str = "transfer_allow_death";
+pub const TRANSFER_KEEP_ALIVE: &str = "transfer_keep_alive";
 pub const FORCE_SET_BALANCE: &str = "force_set_balance";
 
 /// Call for a balance transfer.
 pub type TransferAllowDeathCall<Address, Balance> = (CallIndex, Address, Compact<Balance>);
 
+/// Call for a balance transfer.
+pub type TransferKeepAliveCall<Address, Balance> = (CallIndex, Address, Compact<Balance>);
+
 /// Call to the balance of an account.
 pub type ForceSetBalanceCall<Address, Balance> = (CallIndex, Address, Compact<Balance>);
 
@@ -52,6 +56,14 @@ pub trait BalancesExtrinsics {
 		amount: Self::Balance,
 	) -> Option<Self::Extrinsic<TransferAllowDeathCall<Self::Address, Self::Balance>>>;
 
+	/// Transfer some liquid free balance to another account.
+	#[allow(clippy::type_complexity)]
+	async fn balance_transfer_keep_alive(
+		&self,
+		to: Self::Address,
+		amount: Self::Balance,
+	) -> Option<Self::Extrinsic<TransferKeepAliveCall<Self::Address, Self::Balance>>>;
+
 	///  Set the balances of a given account.
 	#[allow(clippy::type_complexity)]
 	async fn balance_force_set_balance(
@@ -85,6 +97,15 @@ where
 		compose_extrinsic!(self, BALANCES_MODULE, TRANSFER_ALLOW_DEATH, to, Compact(amount))
 	}
 
+	#[allow(clippy::type_complexity)]
+	async fn balance_transfer_keep_alive(
+		&self,
+		to: Self::Address,
+		amount: Self::Balance,
+	) -> Option<Self::Extrinsic<TransferKeepAliveCall<Self::Address, Self::Balance>>> {
+		compose_extrinsic!(self, BALANCES_MODULE, TRANSFER_KEEP_ALIVE, to, Compact(amount))
+	}
+
 	async fn balance_force_set_balance(
 		&self,
 		who: Self::Address,

testing/async/examples/dispatch_errors_tests.rs

@@ -20,7 +20,7 @@ use sp_keyring::AccountKeyring;
 use sp_runtime::MultiAddress;
 use substrate_api_client::{
 	ac_primitives::AssetRuntimeConfig, extrinsic::BalancesExtrinsics, rpc::JsonrpseeClient, Api,
-	Error, GetAccountInformation, SubmitAndWatch, XtStatus,
+	Error, GetAccountInformation, GetBalance, SubmitAndWatch, XtStatus,
 };
 
 #[tokio::main]
@@ -33,7 +33,7 @@ async fn main() {
 
 	let alice = AccountKeyring::Alice.to_account_id();
 	let balance_of_alice = api.get_account_data(&alice).await.unwrap().unwrap().free;
-	println!("[+] Alice's Free Balance is is {}\n", balance_of_alice);
+	println!("[+] Alice's Free Balance is {}\n", balance_of_alice);
 
 	let bob = AccountKeyring::Bob.to_account_id();
 	let balance_of_bob = api.get_account_data(&bob).await.unwrap().unwrap_or_default().free;
@@ -59,10 +59,10 @@ async fn main() {
 			assert!(report.block_hash.is_some());
 			assert!(report.events.is_some());
 			assert!(format!("{dispatch_error:?}").contains("BadOrigin"));
+			println!("[+] BadOrigin error: Bob can't force set balance");
 		},
 		_ => panic!("Expected Failed Extrinisc Error"),
 	}
-	println!("[+] BadOrigin error: Bob can't force set balance");
 
 	//BelowMinimum
 	api.set_signer(alice_signer.into());
@@ -80,5 +80,9 @@ async fn main() {
 		},
 		_ => panic!("Expected Failed Extrinisc Error"),
 	}
-	println!("[+] BelowMinimum error: balance (999999) is below the existential deposit");
+	let existential_deposit = api.get_existential_deposit().await.unwrap();
+	println!(
+		"[+] BelowMinimum error: balance (999999) is below the existential deposit ({})",
+		&existential_deposit
+	);
 }

testing/async/examples/pallet_balances_tests.rs

@@ -15,15 +15,65 @@
 
 //! Tests for the pallet balances interface functions.
 
+use sp_keyring::AccountKeyring;
 use substrate_api_client::{
-	ac_primitives::AssetRuntimeConfig, rpc::JsonrpseeClient, Api, GetBalance,
+	ac_primitives::AssetRuntimeConfig, extrinsic::BalancesExtrinsics, rpc::JsonrpseeClient, Api,
+	GetAccountInformation, GetBalance, SubmitAndWatch, XtStatus,
 };
 
 #[tokio::main]
 async fn main() {
 	// Setup
 	let client = JsonrpseeClient::with_default_url().await.unwrap();
-	let api = Api::<AssetRuntimeConfig, _>::new(client).await.unwrap();
+	let mut api = Api::<AssetRuntimeConfig, _>::new(client).await.unwrap();
 
-	let _ed = api.get_existential_deposit().await.unwrap();
+	let ed = api.get_existential_deposit().await.unwrap();
+	println!("[+] Existential deposit is {}\n", ed);
+
+	let alice = AccountKeyring::Alice.to_account_id();
+	let alice_signer = AccountKeyring::Alice.pair();
+	api.set_signer(alice_signer.into());
+	let balance_of_alice = api.get_account_data(&alice).await.unwrap().unwrap().free;
+	println!("[+] Alice's Free Balance is {}\n", balance_of_alice);
+
+	let bob = AccountKeyring::Bob.to_account_id();
+	let balance_of_bob = api.get_account_data(&bob).await.unwrap().unwrap_or_default().free;
+	println!("[+] Bob's Free Balance is {}\n", balance_of_bob);
+
+	// Rough estimate of fees for three transactions
+	let fee_estimate = 3 * 2000000000000;
+
+	let xt = api
+		.balance_transfer_keep_alive(bob.clone().into(), balance_of_alice / 2 - fee_estimate)
+		.await
+		.unwrap();
+	let report = api.submit_and_watch_extrinsic_until(xt, XtStatus::Finalized).await;
+	// This call should succeed as alice has enough money
+	assert!(report.is_ok());
+
+	let balance_of_alice = api.get_account_data(&alice).await.unwrap().unwrap().free;
+	println!("[+] Alice's Free Balance is {}\n", balance_of_alice);
+
+	let xt = api
+		.balance_transfer_keep_alive(bob.clone().into(), balance_of_alice - fee_estimate)
+		.await
+		.unwrap();
+	let report = api.submit_and_watch_extrinsic_until(xt, XtStatus::Finalized).await;
+	// This call should fail as alice would fall below the existential deposit
+	assert!(report.is_err());
+
+	let xt = api
+		.balance_transfer_allow_death(bob.clone().into(), balance_of_alice - fee_estimate)
+		.await
+		.unwrap();
+	let result = api.submit_and_watch_extrinsic_until(xt, XtStatus::Finalized).await;
+	// With allow_death the call should succeed
+	assert!(result.is_ok());
+
+	let alice_account = api.get_account_data(&alice).await.unwrap();
+	// Alice account should not exist anymore so we excpect an error
+	assert!(alice_account.is_none());
+
+	let balance_of_bob = api.get_account_data(&bob).await.unwrap().unwrap_or_default().free;
+	println!("[+] Bob's Free Balance is {}\n", balance_of_bob);
 }