NestJS Enterprise Backend APIs · Ders

Akıllı Sözleşmeleri Birim Testine Tabi Tutma

Doğruluklarını, güvenliklerini ve beklenen davranışlarını güvence altına almak için Solidity sözleşmeleriniz için kapsamlı birim testleri yazmayı öğrenin.

Akıllı Sözleşmeleri Birim Testine Tabi Tutma, CoddyKit'te ücretsiz bir NestJS Enterprise Backend APIs dersidir. Bu, 6 dersinin 4. dersidir. Aşağıdan dersin tamamını ücretsiz okuyabilir, sonra tarayıcıda yerleşik kod editörü ve 7/24 yapay zeka koçu ile uygulamalı olarak pratik yapabilirsin. Bu, NestJS Enterprise Backend APIs öğrenme yolunun bir parçasıdır ve ilerlemeniz web ve CoddyKit uygulaması arasında senkronize olur. NestJS Enterprise Backend APIs kursu toplamda 6 dersten oluşur.

Bu dersin bazı bölümleri henüz çevrilmemiş olup İngilizce olarak gösterilmektedir.

Unit Testing Smart Contracts

Welcome to unit testing for smart contracts! This lesson will guide you through writing effective tests for your Solidity code.

Unit tests are crucial in traditional software development, but they are absolutely vital in the blockchain world due to the immutable nature of smart contracts and the financial value they often secure.

Why Test Smart Contracts?

Unlike regular applications, smart contracts, once deployed, cannot be easily changed. Bugs can lead to significant financial losses or system failures.

Immutability: Deployed contracts are permanent.
High Stakes: Often manage valuable assets.
Security: Protect against vulnerabilities.
Reliability: Ensure functions behave as expected.
Gas Costs: Bugs can waste user funds.

Thorough testing helps catch issues before deployment.

Introducing Hardhat for Testing

Hardhat is a popular Ethereum development environment that includes a powerful testing framework. It provides a local Ethereum network (Hardhat Network) for fast, isolated testing.

Local Network: Deploy and test without real gas fees.
Ethers.js Integration: Interact with contracts using a familiar JavaScript library.
Debugging: Tools for understanding transaction failures.

We'll use Hardhat to write our unit tests.

Basic Contract for Testing

Let's start with a simple Solidity contract that we'll use for our unit tests. This Counter contract allows us to increment, decrement, and get a count.

Copy and save this as contracts/Counter.sol in your Hardhat project.

pragma solidity ^0.8.0;

contract Counter {
  uint public count;

  constructor() {
    count = 0;
  }

  function increment() public {
    count += 1;
  }

  function decrement() public {
    require(count > 0, "Count cannot be negative");
    count -= 1;
  }

  function getCount() public view returns (uint) {
    return count;
  }
}

Setting Up Your Test File

Hardhat expects test files to be in the test/ directory. We'll use Mocha for our test runner and Chai for assertions, both integrated with Hardhat.

describe(): Groups related tests.
it(): Defines an individual test case.
beforeEach(): Runs before each test in a describe block, useful for setup.

Let's create a file named test/Counter.js.

Deploying Your Contract in Tests

Before we can test our contract's functions, we need to deploy it to our local Hardhat network. The beforeEach block is perfect for this, ensuring a fresh deployment for every test.

Try running this test file. It should pass if your contract is correctly set up.

const { expect } = require("chai");
const { ethers } = require("hardhat");

describe("Counter", function () {
  let counter; // Declare 'counter' to be accessible in all tests

  beforeEach(async function () {
    const CounterFactory = await ethers.getContractFactory("Counter");
    counter = await CounterFactory.deploy();
    await counter.deployed(); // Wait for deployment to be confirmed
  });

  // A simple test to confirm deployment
  it("Should confirm the contract is deployed", async function () {
    expect(counter.address).to.not.be.null;
  });
});

Testing Initial State

The first thing to test is if our contract's initial state is correct. Our Counter contract's count should start at 0.

We use expect() from Chai to make assertions about our contract's behavior. to.equal() checks for equality.

const { expect } = require("chai");
const { ethers } = require("hardhat");

describe("Counter", function () {
  let counter;

  beforeEach(async function () {
    const CounterFactory = await ethers.getContractFactory("Counter");
    counter = await CounterFactory.deploy();
    await counter.deployed();
  });

  it("Should return the initial count of 0", async function () {
    expect(await counter.getCount()).to.equal(0);
  });

  it("Should confirm the contract is deployed", async function () {
    expect(counter.address).to.not.be.null;
  });
});

Testing State Changes (Increment)

Now let's test a function that changes the contract's state. After calling increment(), we expect the count to increase by one.

Remember that state-changing functions need to be awaited because they involve a transaction on the blockchain.

const { expect } = require("chai");
const { ethers } = require("hardhat");

describe("Counter", function () {
  let counter;

  beforeEach(async function () {
    const CounterFactory = await ethers.getContractFactory("Counter");
    counter = await CounterFactory.deploy();
    await counter.deployed();
  });

  it("Should return the initial count of 0", async function () {
    expect(await counter.getCount()).to.equal(0);
  });

  it("Should increment the count by 1", async function () {
    await counter.increment();
    expect(await counter.getCount()).to.equal(1);
  });

  it("Should confirm the contract is deployed", async function () {
    expect(counter.address).to.not.be.null;
  });
});

Testing Function Logic (Decrement)

We can also test the decrement() function. For this, we first need to increment the counter to ensure count is greater than zero.

This shows how tests can involve a sequence of operations to reach a desired state before asserting the outcome.

const { expect } = require("chai");
const { ethers } = require("hardhat");

describe("Counter", function () {
  let counter;

  beforeEach(async function () {
    const CounterFactory = await ethers.getContractFactory("Counter");
    counter = await CounterFactory.deploy();
    await counter.deployed();
  });

  it("Should return the initial count of 0", async function () {
    expect(await counter.getCount()).to.equal(0);
  });

  it("Should increment the count by 1", async function () {
    await counter.increment();
    expect(await counter.getCount()).to.equal(1);
  });

  it("Should decrement the count by 1", async function () {
    await counter.increment(); // First increment to make count > 0
    await counter.decrement();
    expect(await counter.getCount()).to.equal(0);
  });

  it("Should confirm the contract is deployed", async function () {
    expect(counter.address).to.not.be.null;
  });
});

Testing for Expected Reverts

Smart contracts often use require() or revert() to enforce conditions. It's vital to test that these conditions correctly trigger a revert when violated.

Chai's to.be.revertedWith() assertion allows us to check for specific error messages.

const { expect } = require("chai");
const { ethers } = require("hardhat");

describe("Counter", function () {
  let counter;

  beforeEach(async function () {
    const CounterFactory = await ethers.getContractFactory("Counter");
    counter = await CounterFactory.deploy();
    await counter.deployed();
  });

  it("Should return the initial count of 0", async function () {
    expect(await counter.getCount()).to.equal(0);
  });

  it("Should increment the count by 1", async function () {
    await counter.increment();
    expect(await counter.getCount()).to.equal(1);
  });

  it("Should decrement the count by 1", async function () {
    await counter.increment();
    await counter.decrement();
    expect(await counter.getCount()).to.equal(0);
  });

  it("Should revert if decrementing from zero", async function () {
    await expect(counter.decrement()).to.be.revertedWith("Count cannot be negative");
  });

  it("Should confirm the contract is deployed", async function () {
    expect(counter.address).to.not.be.null;
  });
});

Quick Check: Test Assertions

What are the key benefits of using expect().to.be.revertedWith("...") in smart contract unit tests?

Recap: Unit Testing Power

In this lesson, you've learned the critical importance of unit testing for smart contracts and how to write effective tests using Hardhat, Mocha, and Chai.

Smart contracts require rigorous testing due to their immutability.
Hardhat provides a powerful local environment for fast testing.
You can test initial states, state changes, function logic, and expected reverts.

Mastering unit testing is a fundamental skill for any secure and reliable DApp developer.

Sıkça Sorulan Sorular

“Akıllı Sözleşmeleri Birim Testine Tabi Tutma” dersi ücretsiz mi?

Evet — “Akıllı Sözleşmeleri Birim Testine Tabi Tutma” dersin tüm metni burada web'de ücretsiz olarak okunabilir. Etkileşimli olarak pratik yapmak (yerleşik kod editörü ve 7/24 yapay zeka koçu) ve NestJS Enterprise Backend APIs kursunun geri kalanını açmak için CoddyKit PRO'ya yükselt. NestJS Enterprise Backend APIs kursu toplamda 6 dersten oluşur.

“Akıllı Sözleşmeleri Birim Testine Tabi Tutma” dersinde ne öğreneceğim?

Doğruluklarını, güvenliklerini ve beklenen davranışlarını güvence altına almak için Solidity sözleşmeleriniz için kapsamlı birim testleri yazmayı öğrenin. NestJS Enterprise Backend APIs ile uygulamalı kodu tarayıcıda doğrudan çalıştırarak pratik yaparsın ve 7/24 yapay zeka koçu dersi çalışırken sorularını yanıtlar.

NestJS Enterprise Backend APIs öğrenmeye başlamak için deneyim gerekli mi?

Önceden deneyim gerekmez. CoddyKit'te NestJS Enterprise Backend APIs, başlangıçtan ileri seviyeye kadar yapılandırıldığı için buradan başlayabilir veya başından başlayıp kendi hızında ilerleme yapabilirsin. Bu, 6 dersinin 4. dersidir.

“Akıllı Sözleşmeleri Birim Testine Tabi Tutma” dersi ne kadar sürer?

Çoğu CoddyKit dersi yaklaşık 5–10 dakika sürer. Her biri kısa ve etkileşimli olduğu için sabit ilerleme yaparsın ve web ile uygulama arasında tam olarak bıraktığın yerden devam edebilirsin.

Bu NestJS Enterprise Backend APIs dersinde kod yazıp çalıştırabilir miyim?

Evet. Her NestJS Enterprise Backend APIs dersi yerleşik bir kod editörü içerir, bu sayede tarayıcıda gerçek kod yazıp çalıştırabilir ve anlık yapay zeka geri bildirimi alırsın — yerel kurulum gerekli değildir.

Bu kursun tüm dersleri

Birim ve Uçtan Uca Test
Hardhat ve Truffle Çerçeveleri
API'lerde Performans Testi
Akıllı Sözleşmeleri Birim Testine Tabi Tutma
Docker'la Konteynerleştirme ve Kubernetes
Test Ağlarına ve Ana Ağa Dağıtım

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