Mastering Jest: A Complete Guide to Testing Course

Module 1: Introduction

15 minutes (2 Lessons)

• Topics: What is Jest; the three primary test types (unit, snapshot, integration)

• Hands-on: Explore the “Test with Jest” example and quiz your understanding of Jest fundamentals

Module 2: Setting Up Jest

30 minutes (4 Lessons + Quiz)

• Topics: Configuring Jest for JavaScript and TypeScript; structuring test files; debugging tests

• Hands-on: Install and configure Jest in a sample project; debug a failing test case

Module 3: Jest Matchers

45 minutes (5 Lessons + Quiz)

• Topics: Built-in matchers, error handling, Jest Extended, creating custom matchers

• Hands-on: Write tests using common and extended matchers; build a custom matcher for your data types

Module 4: Writing Unit Tests

45 minutes (5 Lessons + Quiz)

• Topics: Structuring clean unit tests, global helpers, best practices

• Hands-on: Refactor a legacy function into well-organized unit tests with clear assertions

Module 5: Snapshot Testing

30 minutes (4 Lessons + Quiz)

• Topics: Introduction to snapshots, creating and maintaining snapshots, avoiding common pitfalls

• Hands-on: Add snapshot tests for React components or JSON outputs and update snapshots safely

Module 6: Testing Asynchronous Code

45 minutes (5 Lessons + Quiz)

• Topics: Callbacks, Promises, async/await patterns in tests

• Hands-on: Write tests for an API-fetch function using callbacks, Promises, and async/await

Module 7: Mocking Core Functions & Timers

60 minutes (6 Lessons)

• Topics: jest.fn(), timer mocks, class mocks, client/server mocking patterns

• Hands-on: Mock timers and API calls to simulate timeouts and network responses

Module 8: Mocking External Libraries

75 minutes (8 Lessons + Project)

• Topics: Techniques for mocking Axios, date libraries, analytics SDKs, charting packages, and more

• Hands-on: Complete the “Working with Jest Mocks” project, mocking multiple third-party packages

Module 9: Setup & Teardown

30 minutes (4 Lessons + Quiz)

• Topics: Test isolation, global setup/teardown, per-test hooks

• Hands-on: Implement beforeAll/afterAll hooks in a database integration test suite

Module 10: Test Coverage & CI/CD Pipelines

30 minutes (4 Lessons + Quiz)

• Topics: Generating coverage reports, enforcing coverage thresholds, integrating with GitHub Actions and CircleCI

• Hands-on: Configure a GitHub Actions workflow to run Jest tests and upload coverage badges

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