Practice
Direct training with no theory, and free environments to experiment. To learn a concept from the start, use the tracks.
Bug Hunt
Each exercise hides bugs in a function. Write tests that pass on the correct code and catch them all.
6 exercises · 24 planted bugs
Playgrounds
Free environments by technique, with no grade or progress.
- TDD Learning LabTDD. The red, green, refactor cycle, with tests running at every step.
- BDD Collaboration LabBDD. Gherkin scenarios tied to executable steps.
- API Testing SandboxAPI. Real requests to a public API, with assertions on status and body.
- E2E Selector PlaygroundE2E. Robust and brittle selectors on a sample page.
- Contract Testing PlaygroundContract. Contracts between consumer and provider, and what breaks when they diverge.
- Visual Regression PlaygroundVisual. Image comparison and thresholds for acceptable difference.
- Performance Testing PlaygroundPerformance. Simulated load, response times and percentiles.
- Accessibility Testing PlaygroundAccessibility. Automatic scanning with axe and what it cannot see.
- Framework ComparisonFrameworks. The same test written in different frameworks, side by side.