Learning Tracks
Your roadmap to real skills.
Many tracks and dozens of sub-tracks. Every track starts with a free intro lesson.
Learning Tracks
Many tracks and dozens of sub-tracks. Every track starts with a free intro lesson.
The skill that is undertaught, overasked-about, and separates pros from amateurs.
~9 hours · 10 lessons
View track details →Why Testing Matters and the Testing Pyramid
Explain the testing pyramid (unit, integration, e2e), what each layer tests and costs, and the limits of coverage as a metric.
Unit Testing Fundamentals
Write a good unit test with Arrange-Act-Assert, keep tests isolated, and use mocking and stubbing correctly.
Unit Testing in JavaScript and TypeScript
Test functions and modules with Vitest/Jest, mock modules and APIs, and use snapshot testing where it fits.
Unit Testing in Python
Test Python code with pytest fixtures and parametrize, and mock dependencies with unittest.mock.
Integration Testing
Test multiple components together, including real database interactions and API routes, without over-mocking.
End-to-End Testing with Playwright
Automate a browser to test a real user flow end to end, and run those tests headless in CI.
Test-Driven Development
Run the red-green-refactor cycle and judge honestly when TDD helps and when it slows you down.
Running Tests in CI
Run the test suite on every pull request, fail the build on failure, and publish coverage reports.
Passion Project: Add a Real Test Suite
Take an untested project and build a full pyramid of tests wired into CI with a coverage gate.
Testing Job Readiness
Translate testing skills into a resume, portfolio, and interview prep for SDET, QA Automation, and engineering roles.