Lesson 6: Running test giving Cannot find module error

[sanjayojha]

The complied JS code from TypeScript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const hardhat_1 = require("hardhat");
const chai_1 = require("chai");
describe("SimpleStorage", function () {
    let simpleStorage;
    let SimpleStorageFactory;
    beforeEach(async () => {
        SimpleStorageFactory = await hardhat_1.ethers.getContractFactory("SimpleStorage");
        simpleStorage = await SimpleStorageFactory.deploy();
    });
    it("Should start with a Favorite Number 0", async function () {
        let currentValue = await simpleStorage.retrieve();
        (0, chai_1.expect)(currentValue).to.equal(0);
        //assert.equal(currentValue, 0);
    });
});

The actual TypeScript Code

import { ethers } from "hardhat";
import { assert, expect } from "chai";

describe("SimpleStorage", function () {
  let simpleStorage;
  let SimpleStorageFactory;
  beforeEach(async () => {
    SimpleStorageFactory = await ethers.getContractFactory("SimpleStorage");
    simpleStorage = await SimpleStorageFactory.deploy();
  });

  it("Should start with a Favorite Number 0", async function () {
    let currentValue = await simpleStorage.retrieve();
    expect(currentValue).to.equal(0);
    //assert.equal(currentValue, 0);
  });
});

The command I am running on terminal

hardhat test test-deploy.js

This is the following error I am getting

An unexpected error occurred:

Error: Cannot find module 'D:\coding-learning\solidityjsbypatrick\hardhat-simple-storage\test-deploy.js'
Require stack:
- D:\coding-learning\solidityjsbypatrick\hardhat-simple-storage\node_modules\hardhat\node_modules\mocha\lib\mocha.js
- D:\coding-learning\solidityjsbypatrick\hardhat-simple-storage\node_modules\hardhat\node_modules\mocha\index.js
- D:\coding-learning\solidityjsbypatrick\hardhat-simple-storage\node_modules\hardhat\builtin-tasks\test.js
- D:\coding-learning\solidityjsbypatrick\hardhat-simple-storage\node_modules\hardhat\internal\core\tasks\builtin-tasks.js
- D:\coding-learning\solidityjsbypatrick\hardhat-simple-storage\node_modules\hardhat\internal\core\config\config-loading.js
- D:\coding-learning\solidityjsbypatrick\hardhat-simple-storage\node_modules\hardhat\internal\cli\cli.js
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)
    at Function.Module._resolveFilename.sharedData.moduleResolveFilenameHook.installedValue [as _resolveFilename] (D:\coding-learning\solidityjsbypatrick\hardhat-simple-storage\node_modules\@cspotcode\source-map-support\source-map-support.js:811:30)
    at Function.Module._load (node:internal/modules/cjs/loader:778:27)
    at Module.require (node:internal/modules/cjs/loader:1005:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at D:\coding-learning\solidityjsbypatrick\hardhat-simple-storage\node_modules\hardhat\node_modules\mocha\lib\mocha.js:417:36
    at Array.forEach (<anonymous>)
    at Mocha.loadFiles (D:\coding-learning\solidityjsbypatrick\hardhat-simple-storage\node_modules\hardhat\node_modules\mocha\lib\mocha.js:414:14)
    at Mocha.run (D:\coding-learning\solidityjsbypatrick\hardhat-simple-storage\node_modules\hardhat\node_modules\mocha\lib\mocha.js:1015:10)  
    at testFailures (D:\coding-learning\solidityjsbypatrick\hardhat-simple-storage\node_modules\hardhat\src\builtin-tasks\test.ts:99:15) {     
  code: 'MODULE_NOT_FOUND',
  requireStack: [
    'D:\\coding-learning\\solidityjsbypatrick\\hardhat-simple-storage\\node_modules\\hardhat\\node_modules\\mocha\\lib\\mocha.js',
    'D:\\coding-learning\\solidityjsbypatrick\\hardhat-simple-storage\\node_modules\\hardhat\\node_modules\\mocha\\index.js',
    'D:\\coding-learning\\solidityjsbypatrick\\hardhat-simple-storage\\node_modules\\hardhat\\builtin-tasks\\test.js',
    'D:\\coding-learning\\solidityjsbypatrick\\hardhat-simple-storage\\node_modules\\hardhat\\internal\\core\\tasks\\builtin-tasks.js',        
    'D:\\coding-learning\\solidityjsbypatrick\\hardhat-simple-storage\\node_modules\\hardhat\\internal\\core\\config\\config-loading.js',      
    'D:\\coding-learning\\solidityjsbypatrick\\hardhat-simple-storage\\node_modules\\hardhat\\internal\\cli\\cli.js'
  ]
}
error Command failed with exit code 1.

To me it look like I need to import some kind of Mocha package as well. But I can see in actual library there is no such import.

[dibakarsutradhar]

@sanjayojha The typescript compiler is looking for Mocha types to run the tests. Check if you have @types/chai and @types/mocha installed in your project. You can check that from your package.json file. In any case, if any of those mentioned above package doesn't exist, do install them yarn add --dev @types/mocha @types/chai. This should solve the issue.

[sanjayojha]

@sanjayojha The typescript compiler is looking for Mocha types to run the tests. Check if you have @types/chai and @types/mocha installed in your project. You can check that from your package.json file. In any case, if any of those mentioned above package doesn't exist, do install them yarn add --dev @types/mocha @types/chai. This should solve the issue.

Here is my package.json

{
  "name": "hardhat-simple-storage",
  "version": "1.0.0",
  "license": "MIT",
  "devDependencies": {
    "@nomiclabs/hardhat-ethers": "^2.0.0",
    "@nomiclabs/hardhat-etherscan": "^3.1.0",
    "@nomiclabs/hardhat-waffle": "^2.0.0",
    "@types/mocha": "^9.1.1",
    "chai": "^4.2.0",
    "dotenv": "^16.0.1",
    "ethereum-waffle": "^3.0.0",
    "ethers": "^5.0.0",
    "hardhat": "^2.9.9",
    "mocha": "^10.0.0",
    "ts-node": "^10.8.1",
    "typescript": "^4.7.4"
  }
}

Also, I can see they haven't imported Mocha package in their code
https://github.com/PatrickAlphaC/hardhat-simple-storage-fcc/blob/typescript/test/test-deploy.ts

[dibakarsutradhar]

Not necessarily you have to import all the packages in the code file. Some of the packages work in the background. Hence @types/chai is required in your project for typescript to know the types for chai test types. You don't need to install the whole mocha module for typescript projects, only just the types of mocha.

You're missing the @types/chai and @types/node from your package.json. You should install them as dev dependencies and this should solve the error.

Here's a snippet of my package.json for the same project -

"devDependencies": {
    "@nomiclabs/hardhat-ethers": "^2.0.0",
    "@nomiclabs/hardhat-etherscan": "^3.0.3",
    "@nomiclabs/hardhat-waffle": "^2.0.0",
    "@typechain/ethers-v5": "^10.0.0",
    "@typechain/hardhat": "^6.0.0",
    "@types/chai": "^4.3.1",
    "@types/mocha": "^9.1.1",
    "@types/node": "^17.0.36",
    "chai": "^4.2.0",
    "dotenv": "^16.0.1",
    "ethereum-waffle": "^3.0.0",
    "ethers": "^5.0.0",
    "hardhat": "^2.9.6",
    "hardhat-gas-reporter": "^1.0.8",
    "prettier": "^2.6.2",
    "prettier-plugin-solidity": "^1.0.0-beta.19",
    "solidity-coverage": "^0.7.21",
    "ts-node": "^10.8.0",
    "typechain": "^8.0.0",
    "typescript": "^4.7.2"
  },

[sanjayojha]

Thanks. I did install and look like its working, though I have one more mistake running the command
instead of hardhat test test-deploy.js I should have run hardhat test .\test\test-deploy.js. My file is in folder test.
One more question

"devDependencies": {
    "@typechain/ethers-v5": "^10.0.0",
    "@typechain/hardhat": "^6.0.0",  
    "typechain": "^8.0.0",
  },

What we have to do with typechain package here?

I am getting following error. Is that related to above?

I can see following code in https://github.com/PatrickAlphaC/hardhat-simple-storage-fcc/blob/typescript/test/test-deploy.ts

import { SimpleStorage, SimpleStorage__factory } from "../typechain-types"

but its equivalent JS code has nothing like this.
https://github.com/PatrickAlphaC/hardhat-simple-storage-fcc/blob/main/test/test-deploy.js

[sanjayojha]

I missed the Patrcik explanation in the end of tutorial. I was coding in typescript while following the video. And didn't realize all this has been explained in the end of video