feat: pallet asset-rate (#13608)

* poc

* fix: remove AssetIdParameter

* tests: add

* docs: add pallet description

* feat: add benches

* refactor: UnknownAssetId

* fix: normalize mock cfg

* fix: benchmarks

* chore: add weights

* refactor: remove storage getter

* chore: apply suggestions from code review

* docs: add native balance to calls

* chore: apply suggestions from code review

* chore: apply ConversionFromAssetBalance

* tests: update balance mock

* chore: apply suggestions from code review

* ci: set publish to false

* docs: fix missing rustdoc

---------

Co-authored-by: parity-processbot <>

substrate/Cargo.lock

@@ -3634,6 +3634,7 @@ dependencies = [
  "log",
  "node-primitives",
  "pallet-alliance",
+ "pallet-asset-rate",
  "pallet-asset-tx-payment",
  "pallet-assets",
  "pallet-authority-discovery",
@@ -5556,6 +5557,22 @@ dependencies = [
  "sp-std",
 ]
 
+[[package]]
+name = "pallet-asset-rate"
+version = "4.0.0-dev"
+dependencies = [
+ "frame-benchmarking",
+ "frame-support",
+ "frame-system",
+ "pallet-balances",
+ "parity-scale-codec",
+ "scale-info",
+ "sp-core",
+ "sp-io",
+ "sp-runtime",
+ "sp-std",
+]
+
 [[package]]
 name = "pallet-asset-tx-payment"
 version = "4.0.0-dev"

substrate/Cargo.toml

@@ -166,6 +166,7 @@ members = [
 	"frame/transaction-payment/rpc/runtime-api",
 	"frame/transaction-storage",
 	"frame/treasury",
+	"frame/asset-rate",
 	"frame/tips",
 	"frame/uniques",
 	"frame/utility",

substrate/bin/node/runtime/Cargo.toml

@@ -53,6 +53,7 @@ frame-election-provider-support = { version = "4.0.0-dev", default-features = fa
 frame-system-rpc-runtime-api = { version = "4.0.0-dev", default-features = false, path = "../../../frame/system/rpc/runtime-api/" }
 frame-try-runtime = { version = "0.10.0-dev", default-features = false, path = "../../../frame/try-runtime", optional = true }
 pallet-alliance = { version = "4.0.0-dev", default-features = false, path = "../../../frame/alliance" }
+pallet-asset-rate = { version = "4.0.0-dev", default-features = false, path = "../../../frame/asset-rate" }
 pallet-assets = { version = "4.0.0-dev", default-features = false, path = "../../../frame/assets" }
 pallet-authority-discovery = { version = "4.0.0-dev", default-features = false, path = "../../../frame/authority-discovery" }
 pallet-authorship = { version = "4.0.0-dev", default-features = false, path = "../../../frame/authorship" }
@@ -201,6 +202,7 @@ std = [
 	"pallet-transaction-payment/std",
 	"pallet-transaction-storage/std",
 	"pallet-treasury/std",
+	"pallet-asset-rate/std",
 	"sp-transaction-pool/std",
 	"pallet-utility/std",
 	"sp-version/std",
@@ -272,6 +274,7 @@ runtime-benchmarks = [
 	"pallet-tips/runtime-benchmarks",
 	"pallet-transaction-storage/runtime-benchmarks",
 	"pallet-treasury/runtime-benchmarks",
+	"pallet-asset-rate/runtime-benchmarks",
 	"pallet-utility/runtime-benchmarks",
 	"pallet-uniques/runtime-benchmarks",
 	"pallet-nfts/runtime-benchmarks",
@@ -333,6 +336,7 @@ try-runtime = [
 	"pallet-timestamp/try-runtime",
 	"pallet-tips/try-runtime",
 	"pallet-treasury/try-runtime",
+	"pallet-asset-rate/try-runtime",
 	"pallet-utility/try-runtime",
 	"pallet-transaction-payment/try-runtime",
 	"pallet-asset-tx-payment/try-runtime",

substrate/bin/node/runtime/src/lib.rs

@@ -1131,6 +1131,17 @@ impl pallet_treasury::Config for Runtime {
 	type SpendOrigin = EnsureWithSuccess<EnsureRoot<AccountId>, AccountId, MaxBalance>;
 }
 
+impl pallet_asset_rate::Config for Runtime {
+	type CreateOrigin = EnsureRoot<AccountId>;
+	type RemoveOrigin = EnsureRoot<AccountId>;
+	type UpdateOrigin = EnsureRoot<AccountId>;
+	type Balance = Balance;
+	type Currency = Balances;
+	type AssetId = u32;
+	type RuntimeEvent = RuntimeEvent;
+	type WeightInfo = pallet_asset_rate::weights::SubstrateWeight<Runtime>;
+}
+
 parameter_types! {
 	pub const BountyCuratorDeposit: Permill = Permill::from_percent(50);
 	pub const BountyValueMinimum: Balance = 5 * DOLLARS;
@@ -1765,6 +1776,7 @@ construct_runtime!(
 		TechnicalMembership: pallet_membership::<Instance1>,
 		Grandpa: pallet_grandpa,
 		Treasury: pallet_treasury,
+		AssetRate: pallet_asset_rate,
 		Contracts: pallet_contracts,
 		Sudo: pallet_sudo,
 		ImOnline: pallet_im_online,
@@ -1922,6 +1934,7 @@ mod benches {
 		[pallet_tips, Tips]
 		[pallet_transaction_storage, TransactionStorage]
 		[pallet_treasury, Treasury]
+		[pallet_asset_rate, AssetRate]
 		[pallet_uniques, Uniques]
 		[pallet_nfts, Nfts]
 		[pallet_utility, Utility]

substrate/frame/asset-rate/Cargo.toml

@@ -0,0 +1,52 @@
+[package]
+name = "pallet-asset-rate"
+version = "4.0.0-dev"
+description = "Whitelist non-native assets for treasury spending and provide conversion to native balance"
+authors = ["William Freudenberger <w.freude@icloud.com>"]
+homepage = "https://substrate.io"
+edition = "2021"
+license = "Apache-2.0"
+repository = "https://github.com/paritytech/substrate/"
+publish = false
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "3.2.2", default-features = false, features = [
+	"derive",
+] }
+scale-info = { version = "2.1.1", default-features = false, features = ["derive"] }
+frame-benchmarking = { version = "4.0.0-dev", default-features = false, optional = true, path = "../benchmarking" }
+frame-support = { version = "4.0.0-dev", default-features = false, path = "../support" }
+frame-system = { version = "4.0.0-dev", default-features = false, path = "../system" }
+sp-runtime = { version = "7.0.0", default-features = false, path = "../../primitives/runtime" }
+sp-std = { version = "5.0.0", default-features = false, path = "../../primitives/std" }
+
+[dev-dependencies]
+pallet-balances = { version = "4.0.0-dev", path = "../balances" }
+sp-core = { version = "7.0.0", path = "../../primitives/core" }
+sp-io = { version = "7.0.0", path = "../../primitives/io" }
+
+[features]
+default = ["std"]
+std = [
+	"codec/std",
+	"frame-benchmarking?/std",
+	"frame-support/std",
+	"frame-system/std",
+	"scale-info/std",
+	"sp-runtime/std",
+	"sp-std/std",
+]
+runtime-benchmarks = [
+	"frame-benchmarking/runtime-benchmarks",
+	"frame-support/runtime-benchmarks",
+	"frame-system/runtime-benchmarks",
+	"sp-runtime/runtime-benchmarks",
+]
+try-runtime = [
+	"frame-support/try-runtime",
+	"frame-system/try-runtime",
+	"sp-runtime/try-runtime",
+]

substrate/frame/asset-rate/src/benchmarking.rs

@@ -0,0 +1,86 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The crate's benchmarks.
+
+use super::*;
+use crate::{pallet as pallet_asset_rate, Pallet as AssetRate};
+
+use frame_benchmarking::v2::*;
+use frame_support::assert_ok;
+use frame_system::RawOrigin;
+
+const ASSET_ID: u32 = 1;
+
+fn default_conversion_rate() -> FixedU128 {
+	FixedU128::from_u32(1u32)
+}
+
+#[benchmarks(where <T as Config>::AssetId: From<u32>)]
+mod benchmarks {
+	use super::*;
+
+	#[benchmark]
+	fn create() -> Result<(), BenchmarkError> {
+		let asset_id: T::AssetId = ASSET_ID.into();
+		#[extrinsic_call]
+		_(RawOrigin::Root, asset_id, default_conversion_rate());
+
+		assert_eq!(
+			pallet_asset_rate::ConversionRateToNative::<T>::get(asset_id),
+			Some(default_conversion_rate())
+		);
+		Ok(())
+	}
+
+	#[benchmark]
+	fn update() -> Result<(), BenchmarkError> {
+		let asset_id: T::AssetId = ASSET_ID.into();
+		assert_ok!(AssetRate::<T>::create(
+			RawOrigin::Root.into(),
+			asset_id,
+			default_conversion_rate()
+		));
+
+		#[extrinsic_call]
+		_(RawOrigin::Root, asset_id, FixedU128::from_u32(2));
+
+		assert_eq!(
+			pallet_asset_rate::ConversionRateToNative::<T>::get(asset_id),
+			Some(FixedU128::from_u32(2))
+		);
+		Ok(())
+	}
+
+	#[benchmark]
+	fn remove() -> Result<(), BenchmarkError> {
+		let asset_id: T::AssetId = ASSET_ID.into();
+		assert_ok!(AssetRate::<T>::create(
+			RawOrigin::Root.into(),
+			ASSET_ID.into(),
+			default_conversion_rate()
+		));
+
+		#[extrinsic_call]
+		_(RawOrigin::Root, asset_id);
+
+		assert!(pallet_asset_rate::ConversionRateToNative::<T>::get(asset_id).is_none());
+		Ok(())
+	}
+
+	impl_benchmark_test_suite! { AssetRate, crate::mock::new_test_ext(), crate::mock::Test }
+}

substrate/frame/asset-rate/src/lib.rs

@@ -0,0 +1,239 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! # Asset Rate Pallet
+//!
+//! - [`Config`]
+//! - [`Call`]
+//!
+//! ## Overview
+//!
+//! The AssetRate pallet provides means of setting conversion rates for some asset to native
+//! balance.
+//!
+//! The supported dispatchable functions are documented in the [`Call`] enum.
+//!
+//! ### Terminology
+//!
+//! * **Asset balance**: The balance type of an arbitrary asset. The network might only know about
+//!   the identifier of the asset and nothing more.
+//! * **Native balance**: The balance type of the network's native currency.
+//!
+//! ### Goals
+//!
+//! The asset-rate system in Substrate is designed to make the following possible:
+//!
+//! * Providing a soft conversion for the balance of supported assets to a default asset class.
+//! * Updating existing conversion rates.
+//!
+//! ## Interface
+//!
+//! ### Permissioned Functions
+//!
+//! * `create`: Creates a new asset conversion rate.
+//! * `remove`: Removes an existing asset conversion rate.
+//! * `update`: Overwrites an existing assert conversion rate.
+//!
+//! Please refer to the [`Call`] enum and its associated variants for documentation on each
+//! function.
+//!
+//! ### Assumptions
+//!
+//! * Conversion rates are only used as estimates, and are not designed to be precise or closely
+//!   tracking real world values.
+//! * All conversion rates reflect the ration of some asset to native, e.g. native = asset * rate.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use frame_support::traits::{
+	fungible::Inspect,
+	tokens::{Balance, ConversionFromAssetBalance},
+};
+use sp_runtime::{traits::Zero, FixedPointNumber, FixedPointOperand, FixedU128};
+
+pub use pallet::*;
+pub use weights::WeightInfo;
+
+#[cfg(feature = "runtime-benchmarks")]
+pub mod benchmarking;
+#[cfg(test)]
+mod mock;
+#[cfg(test)]
+mod tests;
+pub mod weights;
+
+// Type alias for `frame_system`'s account id.
+type AccountIdOf<T> = <T as frame_system::Config>::AccountId;
+// This pallet's asset id and balance type.
+type AssetIdOf<T> = <T as Config>::AssetId;
+// Generic fungible balance type.
+type BalanceOf<T> = <<T as Config>::Currency as Inspect<AccountIdOf<T>>>::Balance;
+
+#[frame_support::pallet]
+pub mod pallet {
+	use super::*;
+	use frame_support::pallet_prelude::*;
+	use frame_system::pallet_prelude::*;
+
+	#[pallet::pallet]
+	pub struct Pallet<T>(_);
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {
+		/// The Weight information for extrinsics in this pallet.
+		type WeightInfo: WeightInfo;
+
+		/// The runtime event type.
+		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
+
+		/// The origin permissioned to create a conversion rate for an asset.
+		type CreateOrigin: EnsureOrigin<Self::RuntimeOrigin>;
+
+		/// The origin permissioned to remove an existing conversion rate for an asset.
+		type RemoveOrigin: EnsureOrigin<Self::RuntimeOrigin>;
+
+		/// The origin permissioned to update an existiing conversion rate for an asset.
+		type UpdateOrigin: EnsureOrigin<Self::RuntimeOrigin>;
+
+		/// The units in which we record balances.
+		type Balance: Balance + FixedPointOperand;
+
+		/// The currency mechanism for this pallet.
+		type Currency: Inspect<Self::AccountId, Balance = Self::Balance>;
+
+		/// The identifier for the class of asset.
+		type AssetId: frame_support::traits::tokens::AssetId;
+	}
+
+	/// Maps an asset to its fixed point representation in the native balance.
+	///
+	/// E.g. `native_amount = asset_amount * ConversionRateToNative::<T>::get(asset_id)`
+	#[pallet::storage]
+	pub type ConversionRateToNative<T: Config> =
+		StorageMap<_, Blake2_128Concat, T::AssetId, FixedU128, OptionQuery>;
+
+	#[pallet::event]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	pub enum Event<T: Config> {
+		// Some `asset_id` conversion rate was created.
+		AssetRateCreated { asset_id: T::AssetId, rate: FixedU128 },
+		// Some `asset_id` conversion rate was removed.
+		AssetRateRemoved { asset_id: T::AssetId },
+		// Some existing `asset_id` conversion rate was updated from `old` to `new`.
+		AssetRateUpdated { asset_id: T::AssetId, old: FixedU128, new: FixedU128 },
+	}
+
+	#[pallet::error]
+	pub enum Error<T> {
+		/// The given asset ID is unknown.
+		UnknownAssetId,
+		/// The given asset ID already has an assigned conversion rate and cannot be re-created.
+		AlreadyExists,
+	}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
+		/// Initialize a conversion rate to native balance for the given asset.
+		///
+		/// ## Complexity
+		/// - O(1)
+		#[pallet::call_index(0)]
+		#[pallet::weight(T::WeightInfo::create())]
+		pub fn create(
+			origin: OriginFor<T>,
+			asset_id: T::AssetId,
+			rate: FixedU128,
+		) -> DispatchResult {
+			T::CreateOrigin::ensure_origin(origin)?;
+
+			ensure!(
+				!ConversionRateToNative::<T>::contains_key(asset_id),
+				Error::<T>::AlreadyExists
+			);
+			ConversionRateToNative::<T>::set(asset_id, Some(rate));
+
+			Self::deposit_event(Event::AssetRateCreated { asset_id, rate });
+			Ok(())
+		}
+
+		/// Update the conversion rate to native balance for the given asset.
+		///
+		/// ## Complexity
+		/// - O(1)
+		#[pallet::call_index(1)]
+		#[pallet::weight(T::WeightInfo::update())]
+		pub fn update(
+			origin: OriginFor<T>,
+			asset_id: T::AssetId,
+			rate: FixedU128,
+		) -> DispatchResult {
+			T::UpdateOrigin::ensure_origin(origin)?;
+
+			let mut old = FixedU128::zero();
+			ConversionRateToNative::<T>::mutate(asset_id, |maybe_rate| {
+				if let Some(r) = maybe_rate {
+					old = *r;
+					*r = rate;
+
+					Ok(())
+				} else {
+					Err(Error::<T>::UnknownAssetId)
+				}
+			})?;
+
+			Self::deposit_event(Event::AssetRateUpdated { asset_id, old, new: rate });
+			Ok(())
+		}
+
+		/// Remove an existing conversion rate to native balance for the given asset.
+		///
+		/// ## Complexity
+		/// - O(1)
+		#[pallet::call_index(2)]
+		#[pallet::weight(T::WeightInfo::remove())]
+		pub fn remove(origin: OriginFor<T>, asset_id: T::AssetId) -> DispatchResult {
+			T::RemoveOrigin::ensure_origin(origin)?;
+
+			ensure!(
+				ConversionRateToNative::<T>::contains_key(asset_id),
+				Error::<T>::UnknownAssetId
+			);
+			ConversionRateToNative::<T>::remove(asset_id);
+
+			Self::deposit_event(Event::AssetRateRemoved { asset_id });
+			Ok(())
+		}
+	}
+}
+
+/// Exposes conversion of an arbitrary balance of an asset to native balance.
+impl<T> ConversionFromAssetBalance<BalanceOf<T>, AssetIdOf<T>, BalanceOf<T>> for Pallet<T>
+where
+	T: Config,
+	BalanceOf<T>: FixedPointOperand + Zero,
+{
+	type Error = pallet::Error<T>;
+
+	fn from_asset_balance(
+		balance: BalanceOf<T>,
+		asset_id: AssetIdOf<T>,
+	) -> Result<BalanceOf<T>, pallet::Error<T>> {
+		let rate = pallet::ConversionRateToNative::<T>::get(asset_id)
+			.ok_or(pallet::Error::<T>::UnknownAssetId.into())?;
+		Ok(rate.saturating_mul_int(balance))
+	}
+}

substrate/frame/asset-rate/src/mock.rs

@@ -0,0 +1,100 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The crate's mock.
+
+use crate as pallet_asset_rate;
+use frame_support::traits::{ConstU16, ConstU64};
+use sp_core::H256;
+use sp_runtime::{
+	testing::Header,
+	traits::{BlakeTwo256, IdentityLookup},
+};
+
+type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
+type Block = frame_system::mocking::MockBlock<Test>;
+
+frame_support::construct_runtime!(
+	pub enum Test where
+		Block = Block,
+		NodeBlock = Block,
+		UncheckedExtrinsic = UncheckedExtrinsic,
+	{
+		System: frame_system,
+		AssetRate: pallet_asset_rate,
+		Balances: pallet_balances,
+	}
+);
+
+impl frame_system::Config for Test {
+	type BaseCallFilter = frame_support::traits::Everything;
+	type BlockWeights = ();
+	type BlockLength = ();
+	type DbWeight = ();
+	type RuntimeOrigin = RuntimeOrigin;
+	type RuntimeCall = RuntimeCall;
+	type Index = u64;
+	type BlockNumber = u64;
+	type Hash = H256;
+	type Hashing = BlakeTwo256;
+	type AccountId = u64;
+	type Lookup = IdentityLookup<Self::AccountId>;
+	type Header = Header;
+	type RuntimeEvent = RuntimeEvent;
+	type BlockHashCount = ConstU64<250>;
+	type Version = ();
+	type PalletInfo = PalletInfo;
+	type AccountData = pallet_balances::AccountData<u64>;
+	type OnNewAccount = ();
+	type OnKilledAccount = ();
+	type SystemWeightInfo = ();
+	type SS58Prefix = ConstU16<42>;
+	type OnSetCode = ();
+	type MaxConsumers = frame_support::traits::ConstU32<16>;
+}
+
+impl pallet_balances::Config for Test {
+	type Balance = u64;
+	type DustRemoval = ();
+	type RuntimeEvent = RuntimeEvent;
+	type ExistentialDeposit = ConstU64<1>;
+	type AccountStore = System;
+	type WeightInfo = ();
+	type MaxLocks = ();
+	type MaxReserves = ();
+	type ReserveIdentifier = [u8; 8];
+	type HoldIdentifier = ();
+	type FreezeIdentifier = ();
+	type MaxHolds = ();
+	type MaxFreezes = ();
+}
+
+impl pallet_asset_rate::Config for Test {
+	type WeightInfo = ();
+	type RuntimeEvent = RuntimeEvent;
+	type CreateOrigin = frame_system::EnsureRoot<u64>;
+	type RemoveOrigin = frame_system::EnsureRoot<u64>;
+	type UpdateOrigin = frame_system::EnsureRoot<u64>;
+	type Balance = u64;
+	type Currency = Balances;
+	type AssetId = u32;
+}
+
+// Build genesis storage according to the mock runtime.
+pub fn new_test_ext() -> sp_io::TestExternalities {
+	frame_system::GenesisConfig::default().build_storage::<Test>().unwrap().into()
+}

substrate/frame/asset-rate/src/tests.rs

@@ -0,0 +1,121 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The crate's tests.
+
+use super::*;
+use crate::pallet as pallet_asset_rate;
+use frame_support::{assert_noop, assert_ok};
+use mock::{new_test_ext, AssetRate, RuntimeOrigin, Test};
+use sp_runtime::FixedU128;
+
+const ASSET_ID: u32 = 42;
+
+#[test]
+fn create_works() {
+	new_test_ext().execute_with(|| {
+		assert!(pallet_asset_rate::ConversionRateToNative::<Test>::get(ASSET_ID).is_none());
+		assert_ok!(AssetRate::create(RuntimeOrigin::root(), ASSET_ID, FixedU128::from_float(0.1)));
+
+		assert_eq!(
+			pallet_asset_rate::ConversionRateToNative::<Test>::get(ASSET_ID),
+			Some(FixedU128::from_float(0.1))
+		);
+	});
+}
+
+#[test]
+fn create_existing_throws() {
+	new_test_ext().execute_with(|| {
+		assert!(pallet_asset_rate::ConversionRateToNative::<Test>::get(ASSET_ID).is_none());
+		assert_ok!(AssetRate::create(RuntimeOrigin::root(), ASSET_ID, FixedU128::from_float(0.1)));
+
+		assert_noop!(
+			AssetRate::create(RuntimeOrigin::root(), ASSET_ID, FixedU128::from_float(0.1)),
+			Error::<Test>::AlreadyExists
+		);
+	});
+}
+
+#[test]
+fn remove_works() {
+	new_test_ext().execute_with(|| {
+		assert_ok!(AssetRate::create(RuntimeOrigin::root(), ASSET_ID, FixedU128::from_float(0.1)));
+
+		assert_ok!(AssetRate::remove(RuntimeOrigin::root(), ASSET_ID,));
+		assert!(pallet_asset_rate::ConversionRateToNative::<Test>::get(ASSET_ID).is_none());
+	});
+}
+
+#[test]
+fn remove_unknown_throws() {
+	new_test_ext().execute_with(|| {
+		assert_noop!(
+			AssetRate::remove(RuntimeOrigin::root(), ASSET_ID,),
+			Error::<Test>::UnknownAssetId
+		);
+	});
+}
+
+#[test]
+fn update_works() {
+	new_test_ext().execute_with(|| {
+		assert_ok!(AssetRate::create(RuntimeOrigin::root(), ASSET_ID, FixedU128::from_float(0.1)));
+		assert_ok!(AssetRate::update(RuntimeOrigin::root(), ASSET_ID, FixedU128::from_float(0.5)));
+
+		assert_eq!(
+			pallet_asset_rate::ConversionRateToNative::<Test>::get(ASSET_ID),
+			Some(FixedU128::from_float(0.5))
+		);
+	});
+}
+
+#[test]
+fn update_unknown_throws() {
+	new_test_ext().execute_with(|| {
+		assert_noop!(
+			AssetRate::update(RuntimeOrigin::root(), ASSET_ID, FixedU128::from_float(0.5)),
+			Error::<Test>::UnknownAssetId
+		);
+	});
+}
+
+#[test]
+fn convert_works() {
+	new_test_ext().execute_with(|| {
+		assert_ok!(AssetRate::create(RuntimeOrigin::root(), ASSET_ID, FixedU128::from_float(2.51)));
+
+		let conversion = <AssetRate as ConversionFromAssetBalance<
+			BalanceOf<Test>,
+			<Test as pallet_asset_rate::Config>::AssetId,
+			BalanceOf<Test>,
+		>>::from_asset_balance(10, ASSET_ID);
+		assert_eq!(conversion.expect("Conversion rate exists for asset"), 25);
+	});
+}
+
+#[test]
+fn convert_unknown_throws() {
+	new_test_ext().execute_with(|| {
+		let conversion = <AssetRate as ConversionFromAssetBalance<
+			BalanceOf<Test>,
+			<Test as pallet_asset_rate::Config>::AssetId,
+			BalanceOf<Test>,
+		>>::from_asset_balance(10, ASSET_ID);
+		assert!(conversion.is_err());
+	});
+}

substrate/frame/asset-rate/src/weights.rs

@@ -0,0 +1,129 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Autogenerated weights for pallet_asset_rate
+//!
+//! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 4.0.0-dev
+//! DATE: 2023-03-16, STEPS: `50`, REPEAT: `20`, LOW RANGE: `[]`, HIGH RANGE: `[]`
+//! WORST CASE MAP SIZE: `1000000`
+//! HOSTNAME: `local`, CPU: `<UNKNOWN>`
+//! EXECUTION: Some(Wasm), WASM-EXECUTION: Compiled, CHAIN: Some("dev"), DB CACHE: 1024
+
+// Executed Command:
+// ./target/production/substrate
+// benchmark
+// pallet
+// --chain=dev
+// --steps=50
+// --repeat=20
+// --pallet=pallet_asset_rate
+// --extrinsic=*
+// --execution=wasm
+// --wasm-execution=compiled
+// --heap-pages=4096
+// --output=./frame/asset-rate/src/weights.rs
+// --header=./HEADER-APACHE2
+// --template=./.maintain/frame-weight-template.hbs
+
+#![cfg_attr(rustfmt, rustfmt_skip)]
+#![allow(unused_parens)]
+#![allow(unused_imports)]
+
+use frame_support::{traits::Get, weights::{Weight, constants::RocksDbWeight}};
+use sp_std::marker::PhantomData;
+
+/// Weight functions needed for pallet_asset_rate.
+pub trait WeightInfo {
+	fn create() -> Weight;
+	fn update() -> Weight;
+	fn remove() -> Weight;
+}
+
+/// Weights for pallet_asset_rate using the Substrate node and recommended hardware.
+pub struct SubstrateWeight<T>(PhantomData<T>);
+impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
+	/// Storage: AssetRate ConversionRateToNative (r:1 w:1)
+	/// Proof: AssetRate ConversionRateToNative (max_values: None, max_size: Some(36), added: 2511, mode: MaxEncodedLen)
+	fn create() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `76`
+		//  Estimated: `3501`
+		// Minimum execution time: 6_000_000 picoseconds.
+		Weight::from_parts(7_000_000, 3501)
+			.saturating_add(T::DbWeight::get().reads(1_u64))
+			.saturating_add(T::DbWeight::get().writes(1_u64))
+	}
+	/// Storage: AssetRate ConversionRateToNative (r:1 w:1)
+	/// Proof: AssetRate ConversionRateToNative (max_values: None, max_size: Some(36), added: 2511, mode: MaxEncodedLen)
+	fn update() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `137`
+		//  Estimated: `3501`
+		// Minimum execution time: 7_000_000 picoseconds.
+		Weight::from_parts(8_000_000, 3501)
+			.saturating_add(T::DbWeight::get().reads(1_u64))
+			.saturating_add(T::DbWeight::get().writes(1_u64))
+	}
+	/// Storage: AssetRate ConversionRateToNative (r:1 w:1)
+	/// Proof: AssetRate ConversionRateToNative (max_values: None, max_size: Some(36), added: 2511, mode: MaxEncodedLen)
+	fn remove() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `137`
+		//  Estimated: `3501`
+		// Minimum execution time: 7_000_000 picoseconds.
+		Weight::from_parts(8_000_000, 3501)
+			.saturating_add(T::DbWeight::get().reads(1_u64))
+			.saturating_add(T::DbWeight::get().writes(1_u64))
+	}
+}
+
+// For backwards compatibility and tests
+impl WeightInfo for () {
+	/// Storage: AssetRate ConversionRateToNative (r:1 w:1)
+	/// Proof: AssetRate ConversionRateToNative (max_values: None, max_size: Some(36), added: 2511, mode: MaxEncodedLen)
+	fn create() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `76`
+		//  Estimated: `3501`
+		// Minimum execution time: 6_000_000 picoseconds.
+		Weight::from_parts(7_000_000, 3501)
+			.saturating_add(RocksDbWeight::get().reads(1_u64))
+			.saturating_add(RocksDbWeight::get().writes(1_u64))
+	}
+	/// Storage: AssetRate ConversionRateToNative (r:1 w:1)
+	/// Proof: AssetRate ConversionRateToNative (max_values: None, max_size: Some(36), added: 2511, mode: MaxEncodedLen)
+	fn update() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `137`
+		//  Estimated: `3501`
+		// Minimum execution time: 7_000_000 picoseconds.
+		Weight::from_parts(8_000_000, 3501)
+			.saturating_add(RocksDbWeight::get().reads(1_u64))
+			.saturating_add(RocksDbWeight::get().writes(1_u64))
+	}
+	/// Storage: AssetRate ConversionRateToNative (r:1 w:1)
+	/// Proof: AssetRate ConversionRateToNative (max_values: None, max_size: Some(36), added: 2511, mode: MaxEncodedLen)
+	fn remove() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `137`
+		//  Estimated: `3501`
+		// Minimum execution time: 7_000_000 picoseconds.
+		Weight::from_parts(8_000_000, 3501)
+			.saturating_add(RocksDbWeight::get().reads(1_u64))
+			.saturating_add(RocksDbWeight::get().writes(1_u64))
+	}
+}