Guide · Open source
How to use javascript-testing-best-practices: a guide to better JS tests
Updated · written with AI from the project's own documentation and checked against our catalogue data
javascript-testing-best-practices is a written guide, not a software tool. It collects advice on structuring, naming and running tests for JavaScript and Node.js projects, and it links out to many blog posts, books and tools. This page explains how to read it, which sections matter for your work, and how to apply the first example it gives: naming and structuring a test.
JavaScript Testing Best Practicesgoldbergyoni/javascript-testing-best-practices · ★ 24.6k · MIT Install options & downloads Quick start
- 1Get the guide. Open the repository on GitHub to read it online, or clone it with git clone https://github.com/goldbergyoni/javascript-testing-best-practices to read it locally.
- 2Read the golden rule. Start with Section 0 to understand the principle that testing code should be short, flat and easy to read.
- 3Check your test names. Review your existing tests and rename them so each name states the unit, the scenario and the expected result.
- 4Restructure one test. Split a long test into Arrange, Act and Assert sections, keeping Act to about one line.
- 5Pick your area. Go to the backend, frontend or CI section that matches your work and follow the links it provides.
What you need before you start reading
The guide has no installation step and no prerequisites are listed in the source. It assumes you already have working knowledge of JavaScript, so it is best suited to developers who already write some tests and want to improve their structure.
You can read it online, or clone the repository to read it locally. The README gives this command for a local copy:
git clone https://github.com/goldbergyoni/javascript-testing-best-practicesUnderstand the guide's structure
The README is organised into six sections. Section 0 is a single golden rule: design tests to be short, dead-simple, flat and easy to read. Section 1 covers test anatomy, Section 2 covers backend and microservices testing, Section 3 covers frontend testing including component and end-to-end tests, Section 4 covers measuring test effectiveness, and Section 5 covers continuous integration.
Read Section 0 first, since the README says most of the advice below derives from it. Then jump to the area you work in.
- Section 0: The Golden Rule
- Section 1: The Test Anatomy
- Section 2: Backend
- Section 3: Frontend
- Section 4: Measuring Tests Effectiveness
- Section 5: Continuous Integration
Name each test with three parts
Section 1.1 recommends that a test name state three things: what is being tested, the circumstances or scenario, and the expected result. The aim is a test report that people who did not write the code, such as a tester or a DevOps engineer, can understand.
The guide's example names the unit under test ProductService.add, the scenario as no price is specified, and the expectation as the product status is pending approval. Compare that with a vague name like Add product, which does not tell you what broke when the test fails.
- What is being tested?
- Under what circumstances and scenario?
- What is the expected result?
Structure each test with Arrange, Act and Assert
Section 1.2 advises separating each test into three clear sections: Arrange (set up the scenario), Act (run the unit under test, usually one line) and Assert (check the result, usually one line). This lets a reader follow the test without spending effort on it.
The guide shows the same customer classifier test written with and without separation. The version with clear sections is easier to read, and the guide notes the bulk version is harder to interpret. The examples use Jest and Mocha.
- Arrange: create the inputs, stubs and records the test needs
- Act: call the code under test once
- Assert: check the received value against the expectation
describe("Customer classifier", () => {
test("When customer spent more than 500$, should be classified as premium", () => {
//Arrange
const customerToClassify = { spent: 505, joined: new Date(), id: 1 };
const DBStub = sinon.stub(dataAccess, "getCustomer").reply({ id: 1, classification: "regular" });
//Act
const receivedClassification = customerClassifier.classifyCustomer(customerToClassify);
//Assert
expect(receivedClassification).toMatch("premium");
});
});Explore the backend, frontend and CI sections
The guide's later sections cover the areas beyond unit tests. The README's introduction lists topics such as testing in production, mutation testing and property-based testing as advanced material. The README also states that the guide summarises and links to many blog posts, books and tools, so expect to follow links for depth.
Choose the section that matches your role. Backend developers and microservice teams should start with Section 2, frontend developers with Section 3, and teams reviewing pipelines with Section 5.
- Backend and microservices: Section 2
- Frontend, component and E2E tests: Section 3
- Measuring test quality: Section 4
- Continuous integration: Section 5
What people use it for
- A backend developer improving test names for a Node.js service so failed deployments are easier to diagnose.
- A frontend developer deciding how to balance component tests and end-to-end tests.
- A team reviewing its continuous integration pipeline for JavaScript code against the CI section.
- A developer refactoring a messy test file into clear Arrange, Act and Assert blocks.
Frequently asked questions
Is javascript-testing-best-practices a tool I can install?
No. The repository is documentation only, so there is nothing to install or run. You read it online or clone the repository to read it locally.
Is javascript-testing-best-practices free?
The repository is licensed under MIT and the guide is available to read in the repository. The README also promotes a paid course by its author, which is separate from the guide itself.
What do I need to know before reading this guide?
The guide assumes working knowledge of JavaScript. The source lists no other prerequisites, and it is not a step-by-step tutorial for complete beginners.
Does the guide cover frontend testing?
Yes. Section 3 covers writing tests for web UI, including component and end-to-end tests. Section 2 covers backend and microservices testing.
What are good alternatives to this guide?
The source lists Kent C. Dodds' Testing JavaScript resources, the Jest documentation and Testing Library as comparable projects. Those are useful if you want library-specific documentation alongside general advice.
Is this guide a substitute for learning a testing library?
Not really. The guide is advice-focused, so it does not replace the documentation for a specific tool. Pair it with a library's docs, such as Jest's, to see how the examples are written in practice.
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Our verdict
Use this guide if you already write JavaScript tests and want better structure, naming and advice for backend, frontend or CI work. Pick something else if you are a complete beginner or need a runnable tool or step-by-step course, since the repository is documentation only.
Install options & downloads