Add unit Tests.

packages/snap/package.json

@@ -23,7 +23,8 @@
     "lint:fix": "yarn lint:eslint --fix && yarn lint:misc --write",
     "lint:misc": "prettier '**/*.json' '**/*.md' '!CHANGELOG.md' --ignore-path .gitignore",
     "serve": "mm-snap serve",
-    "start": "mm-snap watch"
+    "start": "mm-snap watch",
+    "test": "mocha --colors -r ts-node/register \"test/**/*.test.ts\""
   },
   "husky": {
     "hooks": {
@@ -50,8 +51,12 @@
     "@metamask/eslint-config-typescript": "^10.0.0",
     "@metamask/key-tree": "^9.0.0",
     "@metamask/snaps-cli": "^0.32.2",
+    "@types/chai": "^4.3.5",
+    "@types/mocha": "^10.0.1",
+    "@types/sinon": "^10.0.16",
     "@typescript-eslint/eslint-plugin": "^5.33.0",
     "@typescript-eslint/parser": "^5.33.0",
+    "chai": "^4.3.7",
     "eslint": "^8.21.0",
     "eslint-config-prettier": "^8.1.0",
     "eslint-plugin-import": "^2.26.0",
@@ -62,11 +67,15 @@
     "ethers": "^5.6.8",
     "husky": "^8.0.3",
     "io-ts": "^2.2.20",
+    "jest": "^29.6.4",
     "lint-staged": "^14.0.0",
+    "mocha": "^10.2.0",
     "prettier": "^2.2.1",
     "prettier-plugin-packagejson": "^2.2.11",
     "rimraf": "^3.0.2",
+    "sinon": "^15.2.0",
     "through2": "^4.0.2",
+    "ts-node": "^10.9.1",
     "typescript": "^4.7.4"
   },
   "packageManager": "yarn@3.2.1",

packages/snap/snap.manifest.json

@@ -7,7 +7,7 @@
     "url": "https://github.com/celo-org/gas-snap.git"
   },
   "source": {
-    "shasum": "PYoA3v5TRGUAvOYlwxpFXD+44Pt23MSpeu+gIUpy+O0=",
+    "shasum": "aCQ8/7Ak/aoj7mQrPfFvI2xUW3nR/o1P+qoUNBDpifs=",
     "location": {
       "npm": {
         "filePath": "dist/bundle.js",

packages/snap/src/currency.ts

@@ -114,7 +114,7 @@
   }
 }
 
 /**
  * Finds the optimal gas currency to send a transaction with based on user balances.
  * This may differ from the feeCurrency specified in the transaction body.
  *
@@ -130,6 +130,7 @@
 export async function getOptimalFeeCurrency(
   tx: CeloTransactionRequest,
   wallet: CeloWallet,
+  Contract: any,
 ): Promise<string | undefined> {
   const registry = new Contract(REGISTRY_ADDRESS, REGISTRY_ABI, wallet);
   const sortedOraclesAddress = await registry.getAddressForString(

packages/snap/src/index.ts

@@ -1,6 +1,6 @@
 import { OnRpcRequestHandler } from '@metamask/snaps-types';
 import { CeloProvider, CeloWallet } from '@celo-tools/celo-ethers-wrapper';
-import { constants } from 'ethers';
+import { constants, Contract } from 'ethers';
 import { getNetworkConfig } from './utils/network';
 import { RequestParamsSchema } from './utils/types';
 import { handleNumber } from './utils/utils';
@@ -76,7 +76,7 @@
           throw new Error(REJECTION_MESSAGE);
         }
 
-        tx.feeCurrency ??= await getOptimalFeeCurrency(tx, wallet);
+        tx.feeCurrency ??= await getOptimalFeeCurrency(tx, wallet, Contract);
         const suggestedFeeCurrency = getFeeCurrencyNameFromAddress(
           tx.feeCurrency,
           network.name,
@@ -91,10 +91,10 @@
           ],
           placeholder: `cusd, ceur, creal, celo`,
         });
         if(overrideFeeCurrency === '') {
           overrideFeeCurrency = suggestedFeeCurrency
         }
         if ( VALID_CURRENCIES.includes(overrideFeeCurrency.toLowerCase()) ) {
           tx.feeCurrency = getFeeCurrencyAddressFromName(
             overrideFeeCurrency.toLowerCase(),
             network.name,
@@ -117,7 +117,7 @@
               `${network.explorer}/tx/${txReceipt?.transactionHash}`,
             ],
           });
           return txReceipt?.transactionHash;
         } catch (e) {
           const message = (e as Error).message.includes('insufficient funds')
             ? INSUFFICIENT_FUNDS_MESSAGE

packages/snap/test/constants.test.ts

@@ -0,0 +1,45 @@
+import { BigNumber } from 'ethers';
+import { SortedOraclesRates } from '../src/utils/types';
+// currency.test.ts
+export const REGISTRY_ADDRESS = '0x000000000000000000000000000000000000ce10';
+export const CELO_MAINNET = 'mainnet';
+export const CELO_ALFAJORES = 'alfajores';
+export const cusdAddressAlfajores =
+  '0x874069Fa1Eb16D44d622F2e0Ca25eeA172369bC1';
+export const ceurAddressAlfajores =
+  '0x10c892A6EC43a53E45D0B916B4b7D383B1b78C0F';
+export const crealAddressAlfajores =
+  '0xE4D517785D091D3c54818832dB6094bcc2744545';
+export const cusdAddressMainnet = '0x765DE816845861e75A25fCA122bb6898B8B1282a';
+export const ceurAddressMainnet = '0xD8763CBa276a3738E6DE85b4b3bF5FDed6D6cA73';
+export const crealAddressMainnet = '0xe8537a3d056DA446677B9E9d6c5dB704EaAb4787';
+export const CELO = 'celo';
+export const CUSD = 'cusd';
+export const CEUR = 'ceur';
+export const CREAL = 'creal';
+export const sortedOraclesAddress =
+  '0xEb70DF9C0eCe284A5b7CCb88B9bBdC4d1E453d37';
+export const feeCurrencyWhitelistAddress =
+  '0xd9251192b3aE36CCE34D5D8471815d283B51C706';
+
+export const walletAddressWithMoreUsd =
+  '0x49e3aEA43AaD61d7a47efb2f993Bd9f58db5E60F';
+export const walletAddressWithMoreEur =
+  '0xa6DE49480dE155413f7D802513f409A5b23165F8';
+export const walletAddressWithMoreReal =
+  '0xD355fd821D13F70B6e313D3DE313D05524fc3703';
+export const walletPKWithMoreUsd = // Private keys for these addresses
+  '6820cfce5e3bcfd15e723d1252e05f429969a49dc50e80350c5f67b514871ad3';
+export const walletPKWithMoreEur =
+  'a3a79bfc80b94d1f48f7af82767b4eed8580abe8d7f149460b63807fc217630f';
+export const walletPKWithMoreReal =
+  'd68208fc514505c201221d6d1e03145784046fa07496821a38d64fe3f68ddfd5';
+
+export const addressRatePair: Record<string, BigNumber[]> = {
+  // 1:1 mapping with usd
+  [cusdAddressAlfajores]: [BigNumber.from(100000), BigNumber.from(100)],
+  // 1:1.18 euro to usd
+  [ceurAddressAlfajores]: [BigNumber.from(118000), BigNumber.from(100)],
+  // 1:0.19 real to usd
+  [crealAddressAlfajores]: [BigNumber.from(19000), BigNumber.from(100)],
+};

packages/snap/test/contract.mock.test.ts

@@ -0,0 +1,72 @@
+import { BigNumber } from 'ethers';
+import {
+  sortedOraclesAddress,
+  feeCurrencyWhitelistAddress,
+  addressRatePair,
+  cusdAddressAlfajores,
+  ceurAddressAlfajores,
+  crealAddressAlfajores,
+  walletAddressWithMoreEur,
+  walletAddressWithMoreReal,
+  walletAddressWithMoreUsd,
+} from './constants.test';
+
+export interface Contract {
+  address: string;
+  defaultBalance: BigNumber;
+  getAddressForString: (name: string) => string;
+  getWhitelist: () => string[];
+  medianRate: (address: string) => BigNumber[] | undefined;
+  balanceOf: (address: string) => BigNumber | undefined;
+}
+
+export class ContractMock implements Contract {
+  public address: string;
+  public defaultBalance: BigNumber = BigNumber.from(100000);
+
+  constructor(tokenAddress: string, ABI: any, wallet: any) {
+    this.address = tokenAddress;
+  }
+
+  public getAddressForString(name: string): string {
+    if (name === 'SortedOracles') {
+      return sortedOraclesAddress;
+    } else {
+      return feeCurrencyWhitelistAddress;
+    }
+  }
+
+  public getWhitelist(): string[] {
+    return Object.keys(addressRatePair);
+  }
+
+  public medianRate(address: string): BigNumber[] | undefined {
+    const rate = addressRatePair[address];
+    if (rate !== undefined) {
+      return rate;
+    }
+
+    return undefined;
+  }
+
+  public balanceOf(walletAddress: string): BigNumber | undefined {
+    switch (this.address) {
+      case cusdAddressAlfajores:
+        if (walletAddress === walletAddressWithMoreUsd) {
+          return BigNumber.from(250000); // Make usd balance bigger than euro so that when multiplied with rates >>>
+        } else {
+          return this.defaultBalance;
+        }
+      case crealAddressAlfajores:
+        if (walletAddress === walletAddressWithMoreReal) {
+          return BigNumber.from(700000); // Make real balance bigger than euro & usd so when multiplied with rates >>>
+        } else {
+          return this.defaultBalance;
+        }
+      case ceurAddressAlfajores:
+        return this.defaultBalance; // Since euro already larger than usd & real when used with rates
+      default:
+        return undefined;
+    }
+  }
+}