book

Testing JavaScript Applications

Name: Testing JavaScript Applications
Author: Lucas Fernandes da Costa
ISBN: 9781617297915

by Lucas Fernandes da Costa

May 2021

Intermediate to advanced

512 pages

14h 47m

English

Manning Publications

Audiobook available

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inside front cover
Testing JavaScript Applications
Copyright
dedication
contents
front matter
prefaceacknowledgmentsabout this bookWho should read this bookHow this book is organized: A roadmapAbout the codeSystem requirementsliveBook discussion forumabout the authorabout the cover illustration
Part 1. Testing JavaScript applications
1 An introduction to automated testing
1.1 What is an automated test?1.2 Why automated tests matter1.2.1 Predictability1.2.2 Reproducibility1.2.3 Collaboration1.2.4 SpeedSummary
2 What to test and when?
2.1 The testing pyramid2.2 Unit tests2.3 Integration tests2.4 End-to-end tests2.4.1 Testing HTTP APIs2.4.2 Testing GUIs2.4.3 Acceptance tests and end-to-end tests are not the same2.5 Exploratory testing and the value of QA2.6 Tests, cost, and revenueSummary
Part 2. Writing tests

3 Testing techniques
3.1 Organizing test suites3.1.1 Breaking down tests3.1.2 Parallelism3.1.3 Global hooks3.1.4 Atomicity3.2 Writing good assertions3.2.1 Assertions and error handling3.2.2 Loose assertions3.2.3 Using custom matchers3.2.4 Circular assertions3.3 Test doubles: Mocks, stubs, and spies3.3.1 Mocking imports3.4 Choosing what to test3.4.1 Don’t test third-party software3.4.2 To mock, or not to mock: That’s the question3.4.3 When in doubt, choose integration tests3.5 Code coverage3.5.1 Automated coverage reports3.5.2 Coverage types3.5.3 What coverage is good for and what it isn’tSummary
4 Testing backend applications
4.1 Structuring a testing environment4.1.1 End-to-end testing4.1.2 Integration testing4.1.3 Unit testing4.2 Testing HTTP endpoints4.2.1 Testing middleware4.3 Dealing with external dependencies4.3.1 Integrations with databases4.3.2 Integrations with other APIsSummary
5 Advanced backend testing techniques
5.1 Eliminating nondeterminism5.1.1 Parallelism and shared resources5.1.2 Dealing with time5.2 Reducing costs while preserving quality5.2.1 Reducing overlap between tests5.2.2 Creating transitive guarantees5.2.3 Turning assertions into preconditionsSummary
6 Testing frontend applications
6.1 Introducing JSDOM6.2 Asserting on the DOM6.2.1 Making it easier to find elements6.2.2 Writing better assertions6.3 Handling events6.4 Testing and browser APIs6.4.1 Testing a localStorage integration6.4.2 Testing a History API integration6.5 Dealing with WebSockets and HTTP requests6.5.1 Tests involving HTTP requests6.5.2 Tests involving WebSocketsSummary
7 The React testing ecosystem
7.1 Setting up a test environment for React7.1.1 Setting up a React application7.1.2 Setting up a testing environment7.2 An overview of React testing libraries7.2.1 Rendering components and the DOM7.2.2 React Testing Library7.2.3 Enzyme7.2.4 The React test rendererSummary
8 Testing React applications
8.1 Testing component integration8.1.1 Stubbing components8.2 Snapshot testing8.2.1 Snapshots beyond components8.2.2 Serializers8.3 Testing styles8.4 Component-level acceptance tests and component stories8.4.1 Writing stories8.4.2 Writing documentationSummary
9 Test-driven development
9.1 The philosophy behind test-driven development9.1.1 What test-driven development is9.1.2 Adjusting the size of your iterations9.1.3 Why adopt test-driven development?9.1.4 When not to apply test-driven development9.2 Writing a JavaScript module using TDD9.3 Testing top-down versus testing bottom-up9.3.1 What bottom-up and top-down testing mean9.3.2 How top-down and bottom-up approaches impact a test-driven workflow9.3.3 The pros and cons of bottom-up versus top-down approaches9.4 Balancing maintenance costs, delivery speed, and brittleness9.4.1 Test-driven implementation9.4.2 Test-driven maintenance9.5 Setting up an environment for TDD to succeed9.5.1 Teamwide adoption9.5.2 Keeping distinct lanes9.5.3 Pairing9.5.4 Supplementary testing9.6 TDD, BDD, validations, and specificationsBDD (behavior-driven development)Summary
10 UI-based end-to-end testing
10.1 What are UI-based end-to-end tests?10.2 When to write each type of test10.2.1 UI-based end-to-end tests10.2.2 Pure end-to-end tests10.2.3 Pure UI tests10.2.4 A note on acceptance testing and this chapter’s name10.3 An overview of end-to-end testing tools10.3.1 Selenium10.3.2 Puppeteer10.3.3 Cypress10.3.4 When to choose CypressSummary
11 Writing UI-based end-to-end tests
11.1 Your first UI-based end-to-end tests11.1.1 Setting up a test environment11.1.2 Writing your first tests11.1.3 Sending HTTP requests11.1.4 Sequencing actions11.2 Best practices for end-to-end-tests11.2.1 Page objects11.2.2 Application actions11.3 Dealing with flakiness11.3.1 Avoiding waiting for fixed amounts of time11.3.2 Stubbing uncontrollable factors11.3.3 Retrying tests11.4 Running tests on multiple browsers11.4.1 Using a testing framework to run tests within a browser11.4.2 Running UI-based tests in multiple browsers11.5 Visual regression testsSummary
Part 3. Business impact
12 Continuous integration and continuous delivery
12.1 What are continuous integration and continuous delivery?12.1.1 Continuous integration12.1.2 Continuous delivery12.2 The role of automated tests in a CI/CD pipeline12.3 Version-control checksSummary
13 A culture of quality
13.1 Using type systems to make invalid states unrepresentable13.2 Reviewing code to catch problems machines can’t13.3 Using linters and formatters to produce consistent code13.4 Monitoring your systems to understand how they actually behave13.5 Explaining your software with good documentationSummary
index
inside back cover

Content preview from Testing JavaScript Applications

6 Testing frontend applications

This chapter covers

Replicating a browser’s JavaScript environment in your tests
Asserting on DOM elements
Handling and testing events
Writing tests involving browser APIs
Handling HTTP requests and WebSocket connections

Trying to write a client-side application without using JavaScript is as difficult as baking a dessert without carbohydrates. JavaScript was born to conquer the web, and in browsers, it has shone.

In this chapter, we’ll cover the fundamentals of testing frontend applications. Together, we’ll build a small web client for the backend we wrote in chapter 4 and learn how to test it.

During the process of building and testing this application, I’ll explain the peculiarities of running JavaScript ...

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Testing JavaScript Applications

by Lucas Fernandes da Costa

6 Testing frontend applications

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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