fix: mainnet oracles

Bumps [axios](https://github.com/axios/axios) from 0.19.2 to 0.21.2.
- [Release notes](https://github.com/axios/axios/releases)
- [Changelog](https://github.com/axios/axios/blob/master/CHANGELOG.md)
- [Commits](https://github.com/axios/axios/compare/v0.19.2...v0.21.2)

---
updated-dependencies:
- dependency-name: axios
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

README.md

@@ -2,18 +2,50 @@
 
 A library that has a collection of onchain and offchain gas price oracle URLs
 
+## Supported networks
+
+### Ethereum Mainnet
+
 Current offchain list:
 
 - https://ethgasstation.info/json/ethgasAPI.json
-- https://gas-oracle.zoltu.io/
+- https://etherchain.org/api/gasnow
-- https://www.etherchain.org/api/gasPriceOracle
+- https://blockscout.com/eth/mainnet/api/v1/gas-price-oracle
-- https://gasprice.poa.network/
-- https://www.gasnow.org/api/v3/gas/price
 
 Current onchain list:
 
 - [chainlink](https://etherscan.io/address/0x169e633a2d1e6c10dd91238ba11c4a708dfef37c#readContract)
 
+### Binance Smart Chain
+
+Current offchain list:
+
+- https://ztake.org/
+
+### xDAI Chain
+
+Current offchain list:
+
+- https://blockscout.com/xdai/mainnet/api/v1/gas-price-oracle
+
+### Polygon (Matic) Network
+
+Current offchain list:
+
+- https://gasstation-mainnet.matic.network/
+
+### Arbitrum One
+
+Current offchain list:
+
+- https://ztake.org/
+
+### Avalanche Mainnet
+
+Current offchain list:
+
+- https://ztake.org/
+
 ## Installation
 
 `npm i gas-price-oracle`
@@ -30,8 +62,15 @@ const { GasPriceOracle } = require('gas-price-oracle');
 
 ```js
 const options = {
+  chainId: 1,
   defaultRpc: 'https://api.mycryptoapi.com/eth',
   timeout: 10000,
+  defaultFallbackGasPrices: {
+    instant: 28,
+    fast: 22,
+    standard: 17,
+    low: 11,
+  },
 };
 const oracle = new GasPriceOracle(options);
 // optional fallbackGasPrices

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gas-price-oracle",
-  "version": "0.2.1",
+  "version": "0.4.5",
   "description": "Gas Price Oracle library for Ethereum dApps.",
   "main": "lib/index.js",
   "homepage": "https://github.com/peppersec/gas-price-oracle",
@@ -47,7 +47,7 @@
     "typescript": "^4.0.3"
   },
   "dependencies": {
-    "axios": "^0.19.2",
+    "axios": "^0.21.2",
     "bignumber.js": "^9.0.0"
   },
   "files": [

src/config.ts

@@ -1,92 +0,0 @@
-import { OffChainOracle, OnChainOracle } from './types';
-
-const ethgasstation: OffChainOracle = {
-  name: 'ethgasstation',
-  url: 'https://ethgasstation.info/json/ethgasAPI.json',
-  instantPropertyName: 'fastest',
-  fastPropertyName: 'fast',
-  standardPropertyName: 'average',
-  lowPropertyName: 'safeLow',
-  denominator: 10,
-  additionalDataProperty: null,
-};
-
-const zoltu: OffChainOracle = {
-  name: 'zoltu',
-  url: 'https://gas-oracle.zoltu.io/',
-  instantPropertyName: 'percentile_99',
-  fastPropertyName: 'percentile_90',
-  standardPropertyName: 'percentile_60',
-  lowPropertyName: 'percentile_30',
-  denominator: 1,
-  additionalDataProperty: null,
-};
-
-const etherchain: OffChainOracle = {
-  name: 'etherchain',
-  url: 'https://www.etherchain.org/api/gasPriceOracle',
-  instantPropertyName: 'fastest',
-  fastPropertyName: 'fast',
-  standardPropertyName: 'standard',
-  lowPropertyName: 'safeLow',
-  denominator: 1,
-  additionalDataProperty: null,
-};
-
-const poa: OffChainOracle = {
-  name: 'poa',
-  url: 'https://gasprice.poa.network/',
-  instantPropertyName: 'instant',
-  fastPropertyName: 'fast',
-  standardPropertyName: 'standard',
-  lowPropertyName: 'slow',
-  denominator: 1,
-  additionalDataProperty: null,
-};
-
-const gasNow: OffChainOracle = {
-  name: 'gasNow',
-  url: 'https://www.gasnow.org/api/v3/gas/price?utm_source=gas-price-oracle',
-  instantPropertyName: 'rapid',
-  fastPropertyName: 'fast',
-  standardPropertyName: 'standard',
-  lowPropertyName: 'slow',
-  denominator: 1e9,
-  additionalDataProperty: 'data',
-};
-
-const anyblock: OffChainOracle = {
-  name: 'anyblock',
-  url: 'https://api.anyblock.tools/ethereum/latest-minimum-gasprice',
-  instantPropertyName: 'instant',
-  fastPropertyName: 'fast',
-  standardPropertyName: 'standard',
-  lowPropertyName: 'slow',
-  denominator: 1,
-  additionalDataProperty: null,
-};
-
-const chainlink: OnChainOracle = {
-  name: 'chainlink',
-  callData: '0x50d25bcd',
-  contract: '0x169E633A2D1E6c10dD91238Ba11c4A708dfEF37C',
-  denominator: '1000000000',
-};
-
-export const offChainOracles: { [key: string]: OffChainOracle } = {
-  ethgasstation,
-  anyblock,
-  gasNow,
-  poa,
-  etherchain,
-  zoltu,
-};
-
-export const onChainOracles: { [key: string]: OnChainOracle } = {
-  chainlink,
-};
-
-export default {
-  offChainOracles,
-  onChainOracles,
-};

src/config/arbitrum.ts

@@ -0,0 +1,23 @@
+import { OffChainOracle, OffChainOracles, OnChainOracles } from '../types';
+
+const ztake: OffChainOracle = {
+  name: 'ztake',
+  url: 'https://blockchains.ztake.org/api/h6WnmwNqw9CAJHzej5W4gD6LZ9n7v8EK/gasprice/arb/',
+  instantPropertyName: 'percentile_90',
+  fastPropertyName: 'percentile_80',
+  standardPropertyName: 'percentile_60',
+  lowPropertyName: 'percentile_30',
+  denominator: 1,
+  additionalDataProperty: null,
+};
+
+export const offChainOracles: OffChainOracles = {
+  ztake,
+};
+
+export const onChainOracles: OnChainOracles = {};
+
+export default {
+  offChainOracles,
+  onChainOracles,
+};

src/config/avalanche.ts

@@ -0,0 +1,23 @@
+import { OffChainOracle, OffChainOracles, OnChainOracles } from '../types';
+
+const ztake: OffChainOracle = {
+  name: 'ztake',
+  url: 'https://blockchains.ztake.org/api/h6WnmwNqw9CAJHzej5W4gD6LZ9n7v8EK/gasprice/avax/',
+  instantPropertyName: 'percentile_90',
+  fastPropertyName: 'percentile_80',
+  standardPropertyName: 'percentile_60',
+  lowPropertyName: 'percentile_30',
+  denominator: 1,
+  additionalDataProperty: null,
+};
+
+export const offChainOracles: OffChainOracles = {
+  ztake,
+};
+
+export const onChainOracles: OnChainOracles = {};
+
+export default {
+  offChainOracles,
+  onChainOracles,
+};

src/config/bsc.ts

@@ -0,0 +1,23 @@
+import { OffChainOracle, OffChainOracles, OnChainOracles } from '../types';
+
+const ztake: OffChainOracle = {
+  name: 'ztake',
+  url: 'https://blockchains.ztake.org/api/h6WnmwNqw9CAJHzej5W4gD6LZ9n7v8EK/gasprice/bsc/',
+  instantPropertyName: 'percentile_90',
+  fastPropertyName: 'percentile_80',
+  standardPropertyName: 'percentile_60',
+  lowPropertyName: 'percentile_30',
+  denominator: 1,
+  additionalDataProperty: null,
+};
+
+export const offChainOracles: OffChainOracles = {
+  ztake,
+};
+
+export const onChainOracles: OnChainOracles = {};
+
+export default {
+  offChainOracles,
+  onChainOracles,
+};

src/config/index.ts

@@ -0,0 +1,26 @@
+import { NetworkConfig } from '../types';
+
+import mainnetOracles from './mainnet';
+import bscOracles from './bsc';
+import xdaiOracles from './xdai';
+import polygonOracles from './polygon';
+import arbitrumOracles from './arbitrum';
+import avalancheOracles from './avalanche';
+
+export enum ChainId {
+  MAINNET = 1,
+  BSC = 56,
+  XDAI = 100,
+  POLYGON = 137,
+  ARBITRUM = 42161,
+  AVALANCHE = 43114,
+}
+
+export const NETWORKS: NetworkConfig = {
+  [ChainId.MAINNET]: mainnetOracles,
+  [ChainId.BSC]: bscOracles,
+  [ChainId.XDAI]: xdaiOracles,
+  [ChainId.POLYGON]: polygonOracles,
+  [ChainId.ARBITRUM]: arbitrumOracles,
+  [ChainId.AVALANCHE]: avalancheOracles,
+};

src/config/mainnet.ts

@@ -0,0 +1,68 @@
+import { OffChainOracle, OnChainOracle, OffChainOracles, OnChainOracles } from '../types';
+
+const ethgasstation: OffChainOracle = {
+  name: 'ethgasstation',
+  url: 'https://ethgasstation.info/json/ethgasAPI.json',
+  instantPropertyName: 'fastest',
+  fastPropertyName: 'fast',
+  standardPropertyName: 'average',
+  lowPropertyName: 'safeLow',
+  denominator: 10,
+  additionalDataProperty: null,
+};
+
+const etherchain: OffChainOracle = {
+  name: 'etherchain',
+  url: 'https://etherchain.org/api/gasnow',
+  instantPropertyName: 'rapid',
+  fastPropertyName: 'fast',
+  standardPropertyName: 'standard',
+  lowPropertyName: 'slow',
+  denominator: 1e9,
+  additionalDataProperty: 'data',
+};
+
+// const blockscout: OffChainOracle = {
+//   name: 'blockscout',
+//   url: 'https://blockscout.com/eth/mainnet/api/v1/gas-price-oracle',
+//   instantPropertyName: 'fast',
+//   fastPropertyName: 'average',
+//   standardPropertyName: 'slow',
+//   lowPropertyName: 'slow',
+//   denominator: 1,
+//   additionalDataProperty: null,
+// };
+
+// const anyblock: OffChainOracle = {
+//   name: 'anyblock',
+//   url: 'https://api.anyblock.tools/ethereum/latest-minimum-gasprice',
+//   instantPropertyName: 'instant',
+//   fastPropertyName: 'fast',
+//   standardPropertyName: 'standard',
+//   lowPropertyName: 'slow',
+//   denominator: 1,
+//   additionalDataProperty: null,
+// };
+
+const chainlink: OnChainOracle = {
+  name: 'chainlink',
+  callData: '0x50d25bcd',
+  contract: '0x169E633A2D1E6c10dD91238Ba11c4A708dfEF37C',
+  denominator: '1000000000',
+};
+
+export const offChainOracles: OffChainOracles = {
+  ethgasstation,
+  // anyblock,
+  // blockscout,
+  etherchain,
+};
+
+export const onChainOracles: OnChainOracles = {
+  chainlink,
+};
+
+export default {
+  offChainOracles,
+  onChainOracles,
+};

src/config/polygon.ts

@@ -0,0 +1,23 @@
+import { OffChainOracle, OffChainOracles, OnChainOracles } from '../types';
+
+const maticGasStation: OffChainOracle = {
+  name: 'maticGasStation',
+  url: 'https://gasstation-mainnet.matic.network',
+  instantPropertyName: 'fastest',
+  fastPropertyName: 'fast',
+  standardPropertyName: 'standard',
+  lowPropertyName: 'safeLow',
+  denominator: 1,
+  additionalDataProperty: null,
+};
+
+export const offChainOracles: OffChainOracles = {
+  maticGasStation,
+};
+
+export const onChainOracles: OnChainOracles = {};
+
+export default {
+  offChainOracles,
+  onChainOracles,
+};

src/config/xdai.ts

@@ -0,0 +1,23 @@
+import { OffChainOracle, OffChainOracles, OnChainOracles } from '../types';
+
+const blockscout: OffChainOracle = {
+  name: 'blockscout',
+  url: 'https://blockscout.com/xdai/mainnet/api/v1/gas-price-oracle',
+  instantPropertyName: 'fast',
+  fastPropertyName: 'average',
+  standardPropertyName: 'slow',
+  lowPropertyName: 'slow',
+  denominator: 1,
+  additionalDataProperty: null,
+};
+
+export const offChainOracles: OffChainOracles = {
+  blockscout,
+};
+
+export const onChainOracles: OnChainOracles = {};
+
+export default {
+  offChainOracles,
+  onChainOracles,
+};

src/index.ts

@@ -1,21 +1,50 @@
 import axios from 'axios';
-import config from './config';
-import { GasPrice, OffChainOracle, OnChainOracle, Config, GasPriceKey, Options } from './types';
 import BigNumber from 'bignumber.js';
 
+import { ChainId, NETWORKS } from './config';
+
+import {
+  Config,
+  Options,
+  GasPrice,
+  GasPriceKey,
+  OffChainOracle,
+  OnChainOracle,
+  OnChainOracles,
+  OffChainOracles,
+} from './types';
+
+const defaultFastGas = 22;
 export class GasPriceOracle {
   lastGasPrice: GasPrice;
-  offChainOracles = { ...config.offChainOracles };
+  offChainOracles: OffChainOracles = {};
-  onChainOracles = { ...config.onChainOracles };
+  onChainOracles: OnChainOracles = {};
   configuration: Config = {
+    chainId: ChainId.MAINNET,
     defaultRpc: 'https://api.mycryptoapi.com/eth',
     timeout: 10000,
+    defaultFallbackGasPrices: {
+      instant: defaultFastGas * 1.3,
+      fast: defaultFastGas,
+      standard: defaultFastGas * 0.85,
+      low: defaultFastGas * 0.5,
+    },
   };
 
   constructor(options?: Options) {
     if (options) {
       Object.assign(this.configuration, options);
     }
+
+    this.configuration.defaultFallbackGasPrices = this.normalize(this.configuration.defaultFallbackGasPrices);
+
+    const network = NETWORKS[this.configuration.chainId];
+
+    if (network) {
+      const { offChainOracles, onChainOracles } = network;
+      this.offChainOracles = { ...offChainOracles };
+      this.onChainOracles = { ...onChainOracles };
+    }
   }
 
   async askOracle(oracle: OffChainOracle): Promise<GasPrice> {
@@ -41,7 +70,7 @@ export class GasPriceOracle {
         standard: parseFloat(gas[standardPropertyName]) / denominator,
         low: parseFloat(gas[lowPropertyName]) / denominator,
       };
-      return gasPrices;
+      return this.normalize(gasPrices);
     } else {
       throw new Error(`Fetch gasPrice from ${name} oracle failed. Trying another one...`);
     }
@@ -108,7 +137,25 @@ export class GasPriceOracle {
       const middle = Math.floor(allPrices.length / 2);
       medianGasPrice[type] = isEven ? (allPrices[middle - 1] + allPrices[middle]) / 2.0 : allPrices[middle];
     }
-    return medianGasPrice;
+    return this.normalize(medianGasPrice);
+  }
+  /**
+   * Normalizes GasPrice values to Gwei. No more than 9 decimals basically
+   * @param GasPrice _gas
+   */
+  normalize(_gas: GasPrice): GasPrice {
+    const format = {
+      decimalSeparator: '.',
+      groupSeparator: '',
+    };
+    const decimals = 9;
+
+    const gas: GasPrice = { ..._gas };
+    for (const type of Object.keys(gas) as Array<keyof GasPrice>) {
+      gas[type] = Number(new BigNumber(gas[type]).toFormat(decimals, format));
+    }
+
+    return gas;
   }
 
   async fetchGasPricesOnChain(): Promise<number> {
@@ -142,37 +189,75 @@ export class GasPriceOracle {
     throw new Error('All oracles are down. Probably a network error.');
   }
 
-  async gasPrices(fallbackGasPrices?: GasPrice, median = true): Promise<GasPrice> {
+  async fetchGasPriceFromRpc(): Promise<number> {
-    const defaultFastGas = 22;
+    const rpcUrl = this.configuration.defaultRpc;
-    const defaultFallbackGasPrices = {
+    const body = {
-      instant: defaultFastGas * 1.3,
+      jsonrpc: '2.0',
-      fast: defaultFastGas,
+      id: 1337,
-      standard: defaultFastGas * 0.85,
+      method: 'eth_gasPrice',
-      low: defaultFastGas * 0.5,
+      params: [],
     };
-    this.lastGasPrice = this.lastGasPrice || fallbackGasPrices || defaultFallbackGasPrices;
     try {
-      this.lastGasPrice = median
+      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-        ? await this.fetchMedianGasPriceOffChain()
+      const response = await axios.post(rpcUrl!, body, { timeout: this.configuration.timeout });
-        : await this.fetchGasPricesOffChain();
+      if (response.status === 200) {
-      return this.lastGasPrice;
+        const { result } = response.data;
+        let fastGasPrice = new BigNumber(result);
+        if (fastGasPrice.isZero()) {
+          throw new Error(`Default RPC provides corrupted values`);
+        }
+        fastGasPrice = fastGasPrice.div(1e9);
+        return fastGasPrice.toNumber();
+      }
+
+      throw new Error(`Fetch gasPrice from default RPC failed..`);
     } catch (e) {
-      console.log('Failed to fetch gas prices from offchain oracles. Trying onchain ones...');
+      console.error(e.message);
+      throw new Error('Default RPC is down. Probably a network error.');
+    }
+  }
+
+  async gasPrices(fallbackGasPrices?: GasPrice, median = true): Promise<GasPrice> {
+    this.lastGasPrice = this.lastGasPrice || fallbackGasPrices || this.configuration.defaultFallbackGasPrices;
+
+    if (Object.keys(this.offChainOracles).length > 0) {
+      try {
+        this.lastGasPrice = median
+          ? await this.fetchMedianGasPriceOffChain()
+          : await this.fetchGasPricesOffChain();
+        return this.lastGasPrice;
+      } catch (e) {
+        console.log('Failed to fetch gas prices from offchain oracles...');
+      }
+    }
+
+    if (Object.keys(this.onChainOracles).length > 0) {
+      try {
+        const fastGas = await this.fetchGasPricesOnChain();
+        this.lastGasPrice = this.categorize(fastGas);
+        return this.lastGasPrice;
+      } catch (e) {
+        console.log('Failed to fetch gas prices from onchain oracles...');
+      }
     }
 
     try {
-      const fastGas = await this.fetchGasPricesOnChain();
+      const fastGas = await this.fetchGasPriceFromRpc();
-      this.lastGasPrice = {
+      this.lastGasPrice = this.categorize(fastGas);
-        instant: fastGas * 1.3,
-        fast: fastGas,
-        standard: fastGas * 0.85,
-        low: fastGas * 0.5,
-      };
       return this.lastGasPrice;
     } catch (e) {
-      console.log('Failed to fetch gas prices from onchain oracles. Last known gas will be returned');
+      console.log('Failed to fetch gas prices from default RPC. Last known gas will be returned');
     }
-    return this.lastGasPrice;
+    return this.normalize(this.lastGasPrice);
+  }
+
+  categorize(gasPrice: number): GasPrice {
+    return this.normalize({
+      instant: gasPrice * 1.3,
+      fast: gasPrice,
+      standard: gasPrice * 0.85,
+      low: gasPrice * 0.5,
+    });
   }
 
   addOffChainOracle(oracle: OffChainOracle): void {

src/types.ts

@@ -9,6 +9,8 @@ export type OffChainOracle = {
   additionalDataProperty: string | null;
 };
 
+export type OffChainOracles = { [key: string]: OffChainOracle };
+
 export type OnChainOracle = {
   name: string;
   rpc?: string;
@@ -17,6 +19,13 @@ export type OnChainOracle = {
   denominator: string;
 };
 
+export type OnChainOracles = { [key: string]: OnChainOracle };
+
+export type AllOracles = {
+  offChainOracles: OffChainOracles;
+  onChainOracles: OnChainOracles;
+};
+
 export type GasPrice = {
   [key in GasPriceKey]: number;
 };
@@ -24,8 +33,14 @@ export type GasPrice = {
 export type GasPriceKey = 'instant' | 'fast' | 'standard' | 'low';
 
 export type Options = {
+  chainId?: number;
   defaultRpc?: string;
   timeout?: number;
+  defaultFallbackGasPrices?: GasPrice;
 };
 
 export type Config = Required<Options>;
+
+export type NetworkConfig = {
+  [key in number]: AllOracles;
+};

tests/index.test.ts

@@ -1,14 +1,19 @@
 /* eslint-disable @typescript-eslint/no-non-null-assertion */
 /* eslint-disable @typescript-eslint/no-var-requires */
-import { GasPrice, OffChainOracle } from '../src/types';
-import mockery from 'mockery';
 import chai from 'chai';
-import { onChainOracles, offChainOracles } from '../src/config';
+import mockery from 'mockery';
+import BigNumber from 'bignumber.js';
 
+import { ChainId, NETWORKS } from '../src/config';
 import { GasPriceOracle } from '../src/index';
+
+import { GasPrice, OffChainOracle } from '../src/types';
+
 chai.use(require('chai-as-promised'));
 chai.should();
+
 let oracle = new GasPriceOracle();
+let { onChainOracles, offChainOracles } = oracle;
 
 before('before', function () {
   const axiosMock = {
@@ -24,6 +29,7 @@ before('before', function () {
 
 beforeEach('beforeEach', function () {
   oracle = new GasPriceOracle();
+  ({ onChainOracles, offChainOracles } = oracle);
 });
 
 describe('constructor', function () {
@@ -118,6 +124,37 @@ describe('fetchGasPricesOnChain', function () {
   });
 });
 
+describe('fetchGasPriceFromRpc', function () {
+  it('should work', async function () {
+    const gas: number = await oracle.fetchGasPriceFromRpc();
+    gas.should.be.a('number');
+    gas.should.be.above(1);
+    gas.should.not.be.equal(0);
+  });
+
+  it('should work with custom rpc', async function () {
+    const rpc = 'https://ethereum-rpc.trustwalletapp.com';
+    const oracle = new GasPriceOracle({ defaultRpc: rpc });
+    oracle.configuration.defaultRpc.should.be.equal(rpc);
+    const gas: number = await oracle.fetchGasPriceFromRpc();
+
+    gas.should.be.a('number');
+
+    gas.should.be.above(1);
+    gas.should.not.be.equal(0);
+  });
+
+  it('should throw if default rpc is down', async function () {
+    mockery.enable({ useCleanCache: true, warnOnUnregistered: false });
+    const { GasPriceOracle } = require('../src/index');
+    oracle = new GasPriceOracle();
+    await oracle
+      .fetchGasPriceFromRpc()
+      .should.be.rejectedWith('Default RPC is down. Probably a network error.');
+    mockery.disable();
+  });
+});
+
 describe('gasPrice', function () {
   it('should work', async function () {
     const gas: GasPrice = await oracle.gasPrices();
@@ -204,26 +241,92 @@ describe('fetchMedianGasPriceOffChain', function () {
   });
 });
 
-describe('askOracle', function () {
+describe('normalize result values', function () {
-  it('all oracles should answer', async function () {
+  const wrongDecimalsGas = {
-    for (const o of Object.values(offChainOracles) as Array<OffChainOracle>) {
+    instant: 1.1,
-      try {
+    fast: 2.12345678901,
-        const gas: GasPrice = await oracle.askOracle(o);
+    standard: 3.12345678901,
+    low: 3.1234567890123456789,
+  };
 
-        gas.instant.should.be.a('number');
+  const checkDecimals = (gas: GasPrice) => {
-        gas.fast.should.be.a('number');
+    const gasPrices: number[] = Object.values(gas);
-        gas.standard.should.be.a('number');
-        gas.low.should.be.a('number');
 
-        gas.instant.should.be.at.least(gas.fast); // greater than or equal to the given number.
+    for (const gas of gasPrices) {
-        gas.fast.should.be.at.least(gas.standard);
+      new BigNumber(gas).dp().should.be.at.most(9);
-        gas.standard.should.be.at.least(gas.low);
-        gas.low.should.not.be.equal(0);
-      } catch (e) {
-        console.error(`Failed to get data from ${o.name} oracle`);
-        throw new Error(e);
-      }
     }
+  };
+
+  it('default fallback should be normalized', function () {
+    mockery.enable({ useCleanCache: true, warnOnUnregistered: false });
+
+    const { GasPriceOracle } = require('../src/index');
+    oracle = new GasPriceOracle({
+      defaultFallbackGasPrices: wrongDecimalsGas,
+    });
+    const { configuration } = oracle;
+
+    checkDecimals(configuration.defaultFallbackGasPrices);
+
+    mockery.disable();
+  });
+
+  it('fallback should be normalized', async function () {
+    mockery.enable({ useCleanCache: true, warnOnUnregistered: false });
+
+    const { GasPriceOracle } = require('../src/index');
+    oracle = new GasPriceOracle();
+
+    const gas = await oracle.gasPrices(wrongDecimalsGas);
+
+    checkDecimals(gas);
+    mockery.disable();
+  });
+
+  it('rpc fallback should be normalized', async function () {
+    const { GasPriceOracle } = require('../src/index');
+    oracle = new GasPriceOracle({ chainId: ChainId.ARBITRUM, defaultRpc: 'https://arb1.arbitrum.io/rpc' });
+
+    const { onChainOracles, offChainOracles } = oracle;
+
+    Object.keys(onChainOracles).forEach(chainOracle => oracle.removeOnChainOracle(chainOracle));
+    Object.keys(offChainOracles).forEach(chainOracle => oracle.removeOffChainOracle(chainOracle));
+
+    const gas = await oracle.gasPrices();
+
+    checkDecimals(gas);
+  });
+});
+
+describe('askOracle', function () {
+  const chains = Object.keys(NETWORKS).map(id => Number(id));
+
+  chains.forEach(chainId => {
+    describe(`all ${ChainId[chainId]} oracles should answer`, function () {
+      oracle = new GasPriceOracle({ chainId });
+      ({ offChainOracles } = oracle);
+
+      for (const o of Object.values(offChainOracles) as Array<OffChainOracle>) {
+        it(`check ${o.name}`, async function () {
+          try {
+            const gas: GasPrice = await oracle.askOracle(o);
+
+            gas.instant.should.be.a('number');
+            gas.fast.should.be.a('number');
+            gas.standard.should.be.a('number');
+            gas.low.should.be.a('number');
+
+            gas.instant.should.be.at.least(gas.fast); // greater than or equal to the given number.
+            gas.fast.should.be.at.least(gas.standard);
+            gas.standard.should.be.at.least(gas.low);
+            gas.low.should.not.be.equal(0);
+          } catch (e) {
+            console.error(`Failed to get data from ${o.name} oracle`);
+            throw new Error(e);
+          }
+        });
+      }
+    });
   });
 });
 

yarn.lock

@@ -261,12 +261,12 @@ astral-regex@^1.0.0:
   resolved "https://registry.yarnpkg.com/astral-regex/-/astral-regex-1.0.0.tgz#6c8c3fb827dd43ee3918f27b82782ab7658a6fd9"
   integrity sha512-+Ryf6g3BKoRc7jfp7ad8tM4TtMiaWvbF/1/sQcZPkkS7ag3D5nMBCe2UfOTONtAkaG0tO0ij3C5Lwmf1EiyjHg==
 
-axios@^0.19.2:
+axios@^0.21.2:
-  version "0.19.2"
+  version "0.21.2"
-  resolved "https://registry.yarnpkg.com/axios/-/axios-0.19.2.tgz#3ea36c5d8818d0d5f8a8a97a6d36b86cdc00cb27"
+  resolved "https://registry.yarnpkg.com/axios/-/axios-0.21.2.tgz#21297d5084b2aeeb422f5d38e7be4fbb82239017"
-  integrity sha512-fjgm5MvRHLhx+osE2xoekY70AhARk3a6hkN+3Io1jc00jtquGvxYlKlsFUhmUET0V5te6CcZI7lcv2Ym61mjHA==
+  integrity sha512-87otirqUw3e8CzHTMO+/9kh/FSgXt/eVDvipijwDtEuwbkySWZ9SBm6VEubmJ/kLKEoLQV/POhxXFb66bfekfg==
   dependencies:
-    follow-redirects "1.5.10"
+    follow-redirects "^1.14.0"
 
 balanced-match@^1.0.0:
   version "1.0.0"
@@ -428,13 +428,6 @@ debug@3.2.6:
   dependencies:
     ms "^2.1.1"
 
-debug@=3.1.0:
-  version "3.1.0"
-  resolved "https://registry.yarnpkg.com/debug/-/debug-3.1.0.tgz#5bb5a0672628b64149566ba16819e61518c67261"
-  integrity sha512-OX8XqP7/1a9cqkxYw2yXss15f26NKWBpDXQd0/uK/KPqdQhxbPa994hnzjcE2VqQpDslf55723cKPUOGSmMY3g==
-  dependencies:
-    ms "2.0.0"
-
 debug@^4.0.1, debug@^4.1.1:
   version "4.2.0"
   resolved "https://registry.yarnpkg.com/debug/-/debug-4.2.0.tgz#7f150f93920e94c58f5574c2fd01a3110effe7f1"
@@ -757,12 +750,10 @@ flatted@^2.0.0:
   resolved "https://registry.yarnpkg.com/flatted/-/flatted-2.0.2.tgz#4575b21e2bcee7434aa9be662f4b7b5f9c2b5138"
   integrity sha512-r5wGx7YeOwNWNlCA0wQ86zKyDLMQr+/RB8xy74M4hTphfmjlijTSSXGuH8rnvKZnfT9i+75zmd8jcKdMR4O6jA==
 
-follow-redirects@1.5.10:
+follow-redirects@^1.14.0:
-  version "1.5.10"
+  version "1.14.4"
-  resolved "https://registry.yarnpkg.com/follow-redirects/-/follow-redirects-1.5.10.tgz#7b7a9f9aea2fdff36786a94ff643ed07f4ff5e2a"
+  resolved "https://registry.yarnpkg.com/follow-redirects/-/follow-redirects-1.14.4.tgz#838fdf48a8bbdd79e52ee51fb1c94e3ed98b9379"
-  integrity sha512-0V5l4Cizzvqt5D44aTXbFZz+FtyXV1vrDN6qrelxtfYQKW0KO0W2T/hkE8xvGa/540LkZlkaUjO4ailYTFtHVQ==
+  integrity sha512-zwGkiSXC1MUJG/qmeIFH2HBJx9u0V46QGUe3YR1fXG8bXQxq7fLj0RjLZQ5nubr9qNJUZrH+xUcwXEoXNpfS+g==
-  dependencies:
-    debug "=3.1.0"
 
 fs.realpath@^1.0.0:
   version "1.0.0"
@@ -800,9 +791,9 @@ get-stdin@^6.0.0:
   integrity sha512-jp4tHawyV7+fkkSKyvjuLZswblUtz+SQKzSWnBbii16BuZksJlU1wuBYXY75r+duh/llF1ur6oNwi+2ZzjKZ7g==
 
 glob-parent@^5.0.0, glob-parent@^5.1.0, glob-parent@~5.1.0:
-  version "5.1.1"
+  version "5.1.2"
-  resolved "https://registry.yarnpkg.com/glob-parent/-/glob-parent-5.1.1.tgz#b6c1ef417c4e5663ea498f1c45afac6916bbc229"
+  resolved "https://registry.yarnpkg.com/glob-parent/-/glob-parent-5.1.2.tgz#869832c58034fe68a4093c17dc15e8340d8401c4"
-  integrity sha512-FnI+VGOpnlGHWZxthPGR+QhR78fuiK0sNLkHQv+bL9fQi57lNNdquIbna/WrfROrolq8GK5Ek6BiMwqL/voRYQ==
+  integrity sha512-AOIgSQCepiJYwP3ARnGx+5VnTu2HBYdzbGP45eLw1vr3zB3vZLeyed1sC9hnbcOc9/SrMyM5RPQrkGz4aS9Zow==
   dependencies:
     is-glob "^4.0.1"
 
@@ -1033,9 +1024,9 @@ locate-path@^3.0.0:
     path-exists "^3.0.0"
 
 lodash@^4.17.14, lodash@^4.17.15, lodash@^4.17.19:
-  version "4.17.20"
+  version "4.17.21"
-  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.20.tgz#b44a9b6297bcb698f1c51a3545a2b3b368d59c52"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"
-  integrity sha512-PlhdFcillOINfeV7Ni6oF1TAEayyZBoZ8bcshTHqOYJYlrqzRK5hagpagky5o4HfCzzd1TRkXPMFq6cKk9rGmA==
+  integrity sha512-v2kDEe57lecTulaDIuNTPy3Ry4gLGJ6Z1O3vE1krgXZNrsQ+LFTGHVxVjcXPs17LhbZVGedAJv8XZ1tvj5FvSg==
 
 log-symbols@3.0.0:
   version "3.0.0"
@@ -1116,11 +1107,6 @@ mockery@^2.1.0:
   resolved "https://registry.yarnpkg.com/mockery/-/mockery-2.1.0.tgz#5b0aef1ff564f0f8139445e165536c7909713470"
   integrity sha512-9VkOmxKlWXoDO/h1jDZaS4lH33aWfRiJiNT/tKj+8OGzrcFDLo8d0syGdbsc3Bc4GvRXPb+NMMvojotmuGJTvA==
 
-ms@2.0.0:
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/ms/-/ms-2.0.0.tgz#5608aeadfc00be6c2901df5f9861788de0d597c8"
-  integrity sha1-VgiurfwAvmwpAd9fmGF4jeDVl8g=
-
 ms@2.1.1:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/ms/-/ms-2.1.1.tgz#30a5864eb3ebb0a66f2ebe6d727af06a09d86e0a"
@@ -1609,9 +1595,9 @@ write@1.0.3:
     mkdirp "^0.5.1"
 
 y18n@^4.0.0:
-  version "4.0.0"
+  version "4.0.1"
-  resolved "https://registry.yarnpkg.com/y18n/-/y18n-4.0.0.tgz#95ef94f85ecc81d007c264e190a120f0a3c8566b"
+  resolved "https://registry.yarnpkg.com/y18n/-/y18n-4.0.1.tgz#8db2b83c31c5d75099bb890b23f3094891e247d4"
-  integrity sha512-r9S/ZyXu/Xu9q1tYlpsLIsa3EeLXXk0VwlxqTcFRfg9EhMW+17kbt9G0NrgCmhGb5vT2hyhJZLfDGx+7+5Uj/w==
+  integrity sha512-wNcy4NvjMYL8gogWWYAO7ZFWFfHcbdbE57tZO8e4cbpj8tfUcwrwqSl3ad8HxpYWCdXcJUCeKKZS62Av1affwQ==
 
 yargs-parser@13.1.2, yargs-parser@^13.1.2:
   version "13.1.2"