Develop Reference

How to mock fs module together with unionfs?

I have written a test case that successfully load files into virtual FS, and at the same time mounted a virtual volume as below
describe("should work", () => {
const { vol } = require("memfs");
afterEach(() => vol.reset());
beforeEach(() => {
vol.mkdirSync(process.cwd(), { recursive: true });
jest.resetModules();
jest.resetAllMocks();
});
it("should be able to mock fs that being called in actual code", async () => {
jest.mock("fs", () => {
return ufs //
.use(jest.requireActual("fs"))
.use(createFsFromVolume(vol) as any);
});
jest.mock("fs/promises", () => {
return ufs //
.use(jest.requireActual("fs/promises"))
.use(createFsFromVolume(vol) as any);
});
const { createFsFromVolume } = require("memfs");
const { ufs } = require("unionfs");
const { countFile } = require("../src/ops/fs");
vol.fromJSON(
{
"./some/README.md": "1",
"./some/index.js": "2",
"./destination": null,
},
"/app"
);
const result = ufs.readdirSync(process.cwd());
const result2 = ufs.readdirSync("/app");
const result3 = await countFile("/app");
console.log({ result, result2, result3 });
});
});
By using ufs.readdirSync, I can access to virtual FS and indeed result giving me files that loaded from disc into virtual FS, result2 representing /app which is a new volume created from vol.fromJSON.
Now my problem is I am unable to get the result for result3, which is calling countFile method as below
import fsPromises from "fs/promises";
export const countFile = async (path: string) => {
const result = await fsPromises.readdir(path);
return result.length;
};
I'm getting error
Error: ENOENT: no such file or directory, scandir '/app'
which I think it's because countFile is accessing the actual FS instead of the virtual despite I've had jest.mock('fs/promises')?
Please if anyone can provide some lead?

This is the function you want to unit test.
//CommonJS version
const fsPromises = require('fs/promises');
const countFile = async (path) => {
const result = await fsPromises.readdir(path);
return result.length;
};
module.exports = {
countFile
}
Now, how you would normally go about this, is to mock fsPromises. In this example specifically readdir() since that is the function being used in countFile.
This is what we call: a stub.
A skeletal or special-purpose implementation of a software component, used to develop or test a component that calls or is otherwise dependent on it. It replaces a called component.
const {countFile} = require('./index');
const {readdir} = require("fs/promises");
jest.mock('fs/promises');
beforeEach(() => {
readdir.mockReset();
});
it("When testing countFile, given string, then return files", async () => {
const path = "/path/to/dir";
// vvvvvvv STUB HERE
readdir.mockResolvedValueOnce(["src", "node_modules", "package-lock.json" ,"package.json"]);
const res = await countFile(path);
expect(res).toBe(4);
})
You do this because you're unit testing. You don't want to be dependent on other functions because that fails to be a unit test and more integration test. Secondly, it's a third-party library, which is maintained/tested by someone else.
Here is where your scenario applies. From my perspective, your objective isn't to test countFile() rather, to test fsPromises and maybe test functionality to read virtual file-systems: unionfs. If so then, fsPromises doesn't need to really be mocked.

truffle - artifacts.require is not a function

I am currently learning solidity and creating my first project. I am trying to test the deployment of my contract with truffle and i keep getting the below error
TypeError: artifacts.reqiure is not a function
Syntax looks correct and there are no errors appearing. I have also gone into the truffle console and the migration seems to have deployed ok and Color.json is now in my abis folder as well.
Any help will be appreciated, all files are below.
Color.sol
pragma solidity 0.5.0;
import "./ERC721Full.sol";
contract Color is ERC721Full {
// Initialise function
constructor () ERC721Full("Color", "COLOR") public {
}
}
Color.test.js
const Color = artifacts.reqiure('./Color.sol')
require('chai')
.use(require('chai-as-promised'))
.should()
contract('Color', (accounts) => {
let contract
before(async () => {
contract = await Color.deployed()
})
describe('deployment,', async() => {
it('deploys successfully', async() => {
contract = await Color.deployed()
const address = contract.address
console.log(address)
assert.notEqual(address,"")
assert.notEqual(address, 0x0)
assert.notEqual(address, null)
assert.notEqual(address, undefined)
})
it('has a name', async () => {
const name = await contract.name()
assert.equal(name, 'Color')
})
it('has a symbol', async () => {
const symbol = await contract.symbol()
assert.equal(symbol, 'COLOR')
})
})
})
2_deploy_contracts.js
const Color = artifacts.require("Color");
module.exports = function(deployer) {
deployer.deploy(Color);
};
1_init_migration.js
const Migrations = artifacts.require("Migrations");
module.exports = function(deployer) {
deployer.deploy(Migrations);
};

Make sure you have
require('#nomiclabs/hardhat-truffle5');
Before you're trying to call artifacts.require

You have a typo in Color.test.js
const Color = artifacts.reqiure('./Color.sol')
should be require

I tried out this particular code and it shows out an error message and after looking into the line it is just a small spelling error in this particular line in the color code: -
const Color = artifacts.reqiure('./Color.sol')
Try replacing it with this: -
const Color = artifacts.require('./Color.sol')

How to fix Timeout exceeded error for async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves

I am trying to deploy a simple contract using mocha and ganache, but I got this error:
Acontract
1) "before each" hook for "Deploys a Contract"
0 passing (30s)
1 failing
1) "before each" hook for "Deploys a Contract":
Error: Timeout of 30000ms exceeded. For async tests and hooks, ensure
"done()" is called; if returning a Promise, ensure it resolves.
The contract code :
pragma solidity ^0.4.17;
contract Acontract {
string public message; // new variable
function Acontract(string initialMessage) public {
message = initialMessage;
}
function setMessage(string newMessage) public {
message = newMessage;
}
}
The test file code:
const assert = require('assert');
const ganache = require('ganache-cli');
const Web3 = require('web3');
const web3 = new Web3(ganache.provider());
const { interface, bytecode} = require('../compile');
let accounts;
let result;
beforeEach( async () => {
accounts = await web3.eth.getAccounts();
result = await new web3.eth.Contract(JSON.parse(interface))
.deploy ({ data: bytecode, arguments: ['WOW'] })
.send({ from: accounts[0], gas: '1000000'});
});
describe('Acontract', ()=> {
it('Deploys a Contract', async ()=>{
console.log(result)
});
});
How to solve this error, the code is simple, I tested getting accounts and it was ok, also deploy seems ok, when it comes to sending the code does not work! any suggestions?

I ran into a similar issue and fixed it like this: (You may try number 2 first).
Installed web3#1.0.0-beta.37 (Note: your dependencies can be very different from mine as you are using solidity ^0.4.17)
Added ganache provider in the code.
const assert = require('assert');
const ganache = require('ganache-cli');
const Web3 = require('web3');
//Ganache Provider
const provider = ganache.provider();
const web3 = new Web3(provider);
const { interface, bytecode} = require('../compile');
let accounts;
let result;
beforeEach( async () => {
accounts = await web3.eth.getAccounts();
result = await new web3.eth.Contract(JSON.parse(interface))
.deploy ({ data: bytecode, arguments: ['WOW'] })
.send({ from: accounts[0], gas: '1000000'});
//Set provider
result.setProvider(provider);
});
describe('Acontract', ()=> {
it('Deploys a Contract', async ()=>{
console.log(result)
});
});
"Contract" object structure is changed a bit in this version. So, I had to update compile.js export a bit as well (You may not need it with your version of solidity compiler).

How to mock pg Pool with Sinon

In a previous project I mocked the mysql library with Sinon. I did this like so:
X.js:
const con = mysql.createPool(config.mysql);
...
Some other place in the project:
const rows = await con.query(query, inserts);
...
X.test.js:
const sinon = require('sinon');
const mockMysql = sinon.mock(require('mysql'));
...
mockMysql.expects('createPool').returns({
query: () => {
// Handles the query...
},
...
It worked perfectly.
In another project I am trying to mock pg, again with Sinon.
pool.js:
const { Pool } = require('pg');
const config = require('#blabla/config');
const pool = new Pool(config.get('database'));
module.exports = pool;
Some other place in the project:
const con = await pool.connect();
const result = await con.query(...
Y.test.js:
???
I can't understand how to mock connect().query(). None of the following approaches work:
1:
const { Pool } = require('pg');
const config = require('#blabla/config');
const mockPool = sinon.mock(new Pool(config.get('database')));
...
mockPool.expects('connect').returns({
query: () => {
console.log('query here');
},
});
1 results in no error but the real db connection is used.
2:
const { Pool } = sinon.mock(require('pg'));
const config = require('#blabla/config');
const pool = new Pool(config.get('database'));
pool.expects('connect').returns({
query: () => {
console.log('query here');
},
});
2 => TypeError: Pool is not a constructor
3:
const { Pool } = sinon.mock(require('pg'));
const config = require('#blabla/config');
const pool = sinon.createStubInstance(Pool);
pool.connect.returns({
query: () => {
console.log('query here');
},
});
3 => TypeError: The constructor should be a function.
Can anybody point me in the right direction with how to mock my PostgreSQL connection?

Example: I have postgres.js like this.
const { Pool } = require('pg');
const handler = {
count: async (pgQuery) => {
try {
const pool = new Pool();
const res = await pool.query(pgQuery);
return { count: parseInt(res.rows[0].counter, 10) };
} catch (error) {
// Log/Throw error here.
}
return false;
}
}
module.exports = handler;
The spec test I created on postgres.spec.js is like this.
const { expect } = require('chai');
const sinon = require('sinon');
const pgPool = require('pg-pool');
const handler = require('postgres.js');
describe('Postgres', function () {
it('should have method count that bla bla', async function () {
// Create stub pgPool query.
const postgreeStubQuery = sinon.stub(pgPool.prototype, 'query');
postgreeStubQuery.onFirstCall().throws('XXX');
postgreeStubQuery.onSecondCall().resolves({
rows: [{ counter: 11 }],
});
// Catch case.
const catcher = await handler.count('SELECT COUNT()..');
expect(catcher).to.equal(false);
expect(postgreeStubQuery.calledOnce).to.equal(true);
// Correct case.
const correct = await handler.count('SELECT COUNT()..');
expect(correct).to.deep.equal({ count: 11 });
expect(postgreeStubQuery.calledTwice).to.equal(true);
// Restore stub.
postgreeStubQuery.restore();
});
});
To stub pool.query(), you need to stub pg-pool prototype and method query.
Hope this helps.

Since you're needing to mock the returned results of a query, I think the easiest solution would be to abstract your database from the the code needing the query results. Example being, your query results are returning information about a person. Create a person.js module with specific methods for interacting with the database.
Your other code needing the person information from the database won't know or care what type of database you use or how you connect to it, all they care to know is what methods are exposed from person.js when they require it.
//person.js
const { Pool } = require('pg')
// do other database connection things here
const getPersonById = function (id) {
// use your query here and return the results
}
module.exports = { getPersonById }
Now in your tests, you mock the person module, not the pg module. Imagine if you had 20 some odd tests that all had the mock MySQL pool set up then you changed to pg, you'd have to change all of those, nightmare. But by abstracting your database connection type/setup, it makes testing much easier, because now you just need to stub/mock your person.js module.
const person = require('../person.js') //or whatever relative file path it's in
const sinon = require('sinon')
describe('person.js', function () {
it('is stubbed right now', function () {
const personStub = sinon.stub(person)
personStub.getPersonById.returns('yup')
expect(personStub.getPersonById()).to.eq('yup')
})
})

Below is a simpler approach that means the system-under-test doesn't need any special tricks.
It is comprised of two parts, though the first is "nice to have":
Use a DI framework to inject the pg.Pool. This is a better approach IMO anyway, and fits really well with testing.
In the beforeEach() of the tests, configure the DI framework to use a mock class with sinon.stub instances.
If you aren't using a DI framework, pass the mock as a Pool parameter... but DI is better ;)
The code below is TypeScript using tsyringe, but similar approaches will work fine with plain JavaScript etc.
Somewhere you'll have code that uses pg.Pool. A contrived example:
import { Pool } from 'pg'
...
function getPets(pool: Pool): Promise<Pet[]> {
return pool.connect()
.then(db => db.query(SQL_HERE)
.then(result => {
db.release()
return result.rows // or result.rows.map(something) etc
})
.catch(error => {
db.release()
throw error
})
)
}
That works, and it's fine if you want to pass the Pool instance in. I'd prefer not to, so I use tsyringe like this:
import { container } from 'tsyringe'
...
function getPets(): Promise<Pet[]> {
return container.resolve<Pool>().connect()
.then(...)
}
Exactly the same outcome, but getPets() is cleaner to call - it can be a pain to lug around a Pool instance.
The main of the program would set up an instance in one of a few ways. Here's mine:
...
container.register(Pool, {
useFactory: instanceCachingFactory(() => {
return new Pool(/* any config here */)
})
})
The beauty of this comes out in tests.
The code above (the "system under test") needs a Pool instance, and that instance needs a connect() method that resolves to a class with query() and release() methods.
This is what I used:
class MockPool {
client = {
query: sinon.stub(),
release: sinon.stub()
}
connect () {
return Promise.resolve(this.client)
}
}
Here's the setup of a test using MockPool:
describe('proof', () => {
let mockPool: MockPool
beforeEach(() => {
// Important! See:
// https://github.com/microsoft/tsyringe#clearing-instances
container.clearInstances()
mockPool = new MockPool()
container.registerInstance(Pool, mockPool as unknown as Pool)
})
})
The cast through unknown to Pool is needed because I'm not implementing the whole Pool API, just what I need.
Here's what a test looks like:
it('mocks postgres', async () => {
mockPool.client.query.resolves({
rows: [
{name: 'Woof', kind: 'Dog'},
{name: 'Meow', kind: 'Cat'}
]
})
const r = await getPets()
expect(r).to.deep.equal([
{name: 'Woof', kind: 'Dog'},
{name: 'Meow', kind: Cat'}
])
})
You can easily control what data the mock Postgres Pool returns, or throw errors, etc.

How to authenticate and send contract method using web3.js 1.0

I am confused about how I should be executing a contract's method using the web3 1.0 library.
This code works (so long as I manually unlock the account first):
var contract = new web3.eth.Contract(contractJson, contractAddress);
contract.methods
.transfer("0x0e0479bC23a96F6d701D003c5F004Bb0f28e773C", 1000)
.send({
from: "0x2EBd0A4729129b45b23aAd4656b98026cf67650A"
})
.on('confirmation', (confirmationNumber, receipt) => {
io.emit('confirmation', confirmationNumber);
});
I get this error (if I don't unlock manually first):
Returned error: authentication needed: password or unlock
The above code is an API endpoint in node.js, so I want it to unlock or authenticate programmatically.
There is no method in web3.js 1.0 to unlock the account.
I also don't think this is necessary (at least that's what I am confused about). Since I am managing accounts, I know what the private key is.
I am thinking the transaction needs to be signed with the private key?? Is this correct? Is this effectively the same thing as "unlocking the account"?
I tried doing this:
var contract = new web3.eth.Contract(contractJson, contractAddress);
var tx = {
from: "...{fromAddress -- address that has the private key below}",
to: "...",
value: ...
};
var signed = web3.eth.accounts.signTransaction(tx,
"...{privateKey}");
console.log(signed);
var promise = web3.eth.sendSignedTransaction(signed);
I get this error:
Returned error: The method net_version does not exist/is not available
What is the easiest way to authenticate and submit a transaction?
Ideally, I want to use the first approach in my code sample, as it is the cleanest.

This code allows me to sign a transaction server-side (node.js) using the privateKey from the account I created (using web3.eth.accounts.create()), and send the signed transaction to the network without having to unlock the account.
I am using Geth 1.7.1
var contract = new web3.eth.Contract(contractJson, contractAddress);
var transfer = contract.methods.transfer("0x...", 490);
var encodedABI = transfer.encodeABI();
var tx = {
from: "0x...",
to: contractAddress,
gas: 2000000,
data: encodedABI
};
web3.eth.accounts.signTransaction(tx, privateKey).then(signed => {
var tran = web3.eth.sendSignedTransaction(signed.rawTransaction);
tran.on('confirmation', (confirmationNumber, receipt) => {
console.log('confirmation: ' + confirmationNumber);
});
tran.on('transactionHash', hash => {
console.log('hash');
console.log(hash);
});
tran.on('receipt', receipt => {
console.log('reciept');
console.log(receipt);
});
tran.on('error', console.error);
});

A way to be able to call your contract methods without having to sign the transaction explicitly is this (web3js 1.0.0):
const privateKey = 'e0f3440344e4814d0dea8a65c1b9c488bab4295571c72fb879f5c29c8c861937';
const account = web3.eth.accounts.privateKeyToAccount('0x' + privateKey);
web3.eth.accounts.wallet.add(account);
web3.eth.defaultAccount = account.address;
// ...
contract = new web3.eth.Contract(JSON_INTERFACE, address);
contract.methods.myMethod(myParam1, myParam2)
.send({
from: this.web3.eth.defaultAccount,
gas: myConfig.gas,
gasPrice: myConfig.gasPrice
})

Here's a complete example of how to sign a transaction without a local wallet account. Especially useful if you are using infura for the transaction. This was written for
'use strict';
const Web3 = require('web3');
const wsAddress = 'wss://rinkeby.infura.io/ws';
const contractJson = '(taken from solc or remix online compiler)';
const privateKey = '0xOOOX';
const contractAddress = '0xOOOX';
const walletAddress = '0xOOOX';
const webSocketProvider = new Web3.providers.WebsocketProvider(wsAddress);
const web3 = new Web3(new Web3.providers.WebsocketProvider(webSocketProvider));
const contract = new web3.eth.Contract(
JSON.parse(contractJson),
contractAddress
);
// change this to whatever contract method you are trying to call, E.G. SimpleStore("Hello World")
const query = contract.methods.SimpleStore('Hello World');
const encodedABI = query.encodeABI();
const tx = {
from: walletAddress,
to: contractAddress,
gas: 2000000,
data: encodedABI,
};
const account = web3.eth.accounts.privateKeyToAccount(privateKey);
console.log(account);
web3.eth.getBalance(walletAddress).then(console.log);
web3.eth.accounts.signTransaction(tx, privateKey).then(signed => {
const tran = web3.eth
.sendSignedTransaction(signed.rawTransaction)
.on('confirmation', (confirmationNumber, receipt) => {
console.log('=> confirmation: ' + confirmationNumber);
})
.on('transactionHash', hash => {
console.log('=> hash');
console.log(hash);
})
.on('receipt', receipt => {
console.log('=> reciept');
console.log(receipt);
})
.on('error', console.error);
});
Using
"web3": "1.0.0-beta.30"

This is my implementation using "#truffle/hdwallet-provider": "^2.0.3", "web3": "^1.6.1",
function getWeb3Provider() {
return new HDWalletProvider({
privateKeys: [NFT_MINTER_ACCOUNT_PRIVATE_KEY],
providerOrUrl: BSC_RPC_ENDPOINT,
});
}
const web3 = new Web3(BSC_RPC_ENDPOINT);
const contract = new web3.eth.Contract(
jsonContractABI as unknown as AbiItem[],
NFT_CONTRACT_ADDRESS
);
contract.setProvider(getWeb3Provider());
then in send methods
contract.methods.safeMint(receiverAddress, itemUri).send({
from: NFT_MINTER_ACCOUNT,
});
in call methods
contract.methods.balanceOf(address).call();