add PoolRegistered event

pallets/price-oracle/src/lib.rs

@@ -72,7 +72,11 @@ pub mod pallet {
 	}
 
 	#[pallet::event]
-	pub enum Event<T: Config> {}
+	#[pallet::generate_deposit(pub(crate) fn deposit_event)]
+	pub enum Event<T: Config> {
+		/// Pool was registered. [AssetPair]
+		PoolRegistered(AssetPair),
+	}
 
 	/// The number of assets registered and handled by this pallet.
 	#[pallet::storage]
@@ -127,11 +131,14 @@ impl<T: Config> Pallet<T> {
 			let incremented_asset_count = if let Some(count) = Self::num_of_assets().checked_add(1) {
 				count
 			} else {
+				// We don't want to throw an error here because this method is used in different extrinsics.
+				// We also do not expect to have more than 2^32 assets registered.
 				return
 			};
 			<NumOfTrackedAssets<T>>::put(incremented_asset_count);
 
 			PriceDataTen::<T>::append((asset_pair.name(), BucketQueue::default()));
+			Self::deposit_event(Event::PoolRegistered(asset_pair));
 		}
 	}
 
@@ -143,6 +150,7 @@ impl<T: Config> Pallet<T> {
 			PriceEntry::default()
 		};
 
+		// Invalid values are ignored and not added to the queue.
 		if let Some(new_entry) = previous_entry.calculate_new_price_entry(&price_entry) {
 			PriceDataAccumulator::<T>::insert(asset_pair.name(), new_entry);
 		}
@@ -197,11 +205,13 @@ impl<T: Config> AMMHandlers<T::AccountId, AssetId, AssetPair, Balance> for Price
 		let (price, amount) = if let Some(price_tuple) = amm_transfer.normalize_price() {
 			price_tuple
 		} else {
+			// We don't want to throw an error here because this method is used in different extrinsics.
+			// Invalid prices are ignored and not added to the queue.
 			return;
 		};
 
-		// we assume that zero prices are not valid
-		// zero values are ignored and not added to the queue
+		// We assume that zero values are not valid.
+		// Zero values are ignored and not added to the queue.
 		if price.is_zero() || amount.is_zero() || liq_amount.is_zero() {
 			return;
 		}

pallets/price-oracle/src/tests.rs

@@ -27,6 +27,20 @@ pub fn new_test_ext() -> sp_io::TestExternalities {
 	ext
 }
 
+fn last_events(n: usize) -> Vec<TestEvent> {
+	frame_system::Pallet::<Test>::events()
+		.into_iter()
+		.rev()
+		.take(n)
+		.rev()
+		.map(|e| e.event)
+		.collect()
+}
+
+fn expect_events(e: Vec<TestEvent>) {
+	assert_eq!(last_events(e.len()), e);
+}
+
 #[test]
 fn add_new_asset_pair_should_work() {
 	new_test_ext().execute_with(|| {
@@ -42,6 +56,7 @@ fn add_new_asset_pair_should_work() {
 			<PriceDataTen<Test>>::get().contains(&(ASSET_PAIR_A.name(), BucketQueue::default())),
 			true
 		);
+		expect_events(vec![Event::PoolRegistered(ASSET_PAIR_A).into()]);
 	});
 }
 
@@ -54,6 +69,7 @@ fn add_existing_asset_pair_should_not_work() {
 		);
 		PriceOracle::on_create_pool(ASSET_PAIR_A);
 		assert_storage_noop!(PriceOracle::on_create_pool(ASSET_PAIR_A));
+		expect_events(vec![Event::PoolRegistered(ASSET_PAIR_A).into()]);
 	});
 }