How to directly test a Solidity Library with Hardhat/Chai - solidity

Question

I'm trying to test a Solidity Library directly using hardhat and chaï.
This is a Library example I would like to test:
library LibTest {
function testFunc() public view returns(bool) {
return true;
}
}
and this is how I'm trying to test it.
beforeEach(async () => {
const LibTest = await ethers.getContractFactory("LibTest");
const libTest = await LibTest.deploy();
await libTest.deployed();
})
describe('Testing test()', function () {
it("is working testFunc ?", async function () {
console.log(await libTest.testFunc());
})
})
But I have the error message:
ReferenceError: libTest is not defined
I read everything I can on Chai doc and Hardhat doc but can't found any solution

Answer 1

I would say to use fixture and also utilize waffle and to deploy the library contract once and save the snapshot of the contract:
const {loadFixture } = require('#nomicfoundation/hardhat-network-helpers');
const {expect} = require('chai');
const {ethers, waffle} = require('hardhat');
const {deployContract} = waffle;
const LibArtifact = require('../artifacts/contracts/lib.sol/LibTest.json');
describe("Lib tests", function () {
// We define a fixture to reuse the same setup in every test.
// We use loadFixture to run this setup once, snapshot that state,
// and reset Hardhat Network to that snapshopt in every test.
async function deployOnceFixture() {
const [owner, ...otherAccounts] = await ethers.getSigners();
lib = (await deployContract(owner, LibArtifact));
return { lib, owner, otherAccounts };
}
describe("Testing test()", function () {
it("s working testFunc ?", async function () {
const { lib } = await loadFixture(deployOnceFixture);
expect(await lib.testFunc()).to.be.true;
});
});
});
Instructions to add the waffle plugin:
Hardhat-waffle
Basically, you need to install the libraries:
npm install --save-dev #nomiclabs/hardhat-waffle 'ethereum-waffle#^3.0.0' #nomiclabs/hardhat-ethers 'ethers#^5.0.0'
And then import hardhat-waffle in the hardhat-config.js file:
require("#nomiclabs/hardhat-waffle");
Also, notice I put the test file in a test directory so I needed to go back one folder to find artifacts generated by running npx hardhat compile.
For convenience I pushed the solution in a Github repo: https://github.com/Tahlil/run-solidity-lib

Answer 2

The best way I have found to go about this is to create a LibTest.sol contract that invokes and tests the Lib itself. And just running abstracted tests in JS/TS to invoke the LibTest contract, connecting the Lib.sol contract to it during deployment in Hardhat.
const Lib = await ethers.getContractFactory("Lib");
const lib = await Lib.deploy();
const LibTest = await ethers.getContractFactory("LibTest", {
libraries: {
Lib: lib.address,
},
});
const libTest = await LibTest.deploy();
/// later: console.log(await libTest.testLibFunc());
LibTest.sol:
import "./Lib.sol";
library LibTest {
function testLibFunc() public view returns(bool) {
bool response = Lib.testFunc();
return response;
}
}
Were you able to find a better method?