Add more tests

pallet/staking/src/mock.rs

@@ -315,10 +315,7 @@ impl darwinia_staking::OnSessionEnd<Runtime> for OnDarwiniaSessionEnd {
 	}
 
 	fn reward(who: &AccountId, amount: Balance) -> sp_runtime::DispatchResult {
-		if let Err(e) = Balances::deposit_into_existing(who, amount) {
-			// TODO: log
-			// log::error!("[runtime::staking] reward error: {:?}", e);
-		}
+		let _ = Balances::deposit_into_existing(who, amount);
 
 		Ok(())
 	}
@@ -334,17 +331,12 @@ impl darwinia_staking::OnSessionEnd<Runtime> for OnCrabSessionEnd {
 	}
 
 	fn reward(who: &AccountId, amount: Balance) -> sp_runtime::DispatchResult {
-		if let Err(e) = <Balances as Currency<AccountId>>::transfer(
+		<Balances as Currency<AccountId>>::transfer(
 			&Treasury::account_id(),
 			who,
 			amount,
 			frame_support::traits::ExistenceRequirement::KeepAlive,
-		) {
-			// TODO: log
-			// log::error!("[runtime::staking] reward error: {:?}", e);
-		}
-
-		Ok(())
+		)
 	}
 }
 impl darwinia_staking::Config for Runtime {

pallet/staking/src/tests.rs

@@ -639,6 +639,31 @@ fn payout_should_work() {
 			Balances::free_balance(&Treasury::account_id()),
 			1_000_000 * UNIT - rewards.iter().sum::<Balance>()
 		);
+
+		dbg!(Balances::free_balance(&Treasury::account_id()));
+		assert_ok!(Balances::transfer_all(
+			RuntimeOrigin::signed(Treasury::account_id()),
+			Default::default(),
+			false
+		));
+		dbg!(Balances::free_balance(&Treasury::account_id()));
+		Staking::reward_by_ids(&[(1, 20)]);
+		System::reset_events();
+		new_session();
+
+		assert_eq!(
+			System::events()
+				.into_iter()
+				.filter_map(|e| match e.event {
+					RuntimeEvent::Staking(e @ Event::Unpaied { .. }) => Some(e),
+					_ => None,
+				})
+				.collect::<Vec<_>>(),
+			vec![
+				Event::Unpaied { staker: 6, amount: 7499999997000000000000 },
+				Event::Unpaied { staker: 1, amount: 2499999994000000000000 }
+			]
+		);
 	});
 }