How to test a frontend game

[atrieongithubappdev]

Purpose

This issue is a comprehensive testing guide for games built with HTML, CSS, and JavaScript. Use this as a checklist and reference for manual, automated, and exploratory testing.

Scope

This guide covers: unit testing, integration testing, end-to-end testing, visual/regression testing, performance, accessibility, cross-browser/device testing, and playtesting.

Checklist

1. Test plan and priority

1.1 Define critical game flows

1.1.1 Player can start a new game

1.1.2 Game state transitions (start, pause, resume, win, lose)

1.1.3 Scoring and persistence (high scores, localStorage)

1.1.4 Input handling (mouse, keyboard, touch)

1.2 Risk areas to test first

1.2.1 Timing logic (timers, intervals)

1.2.2 Randomization (shuffling, RNG seed behavior)

1.2.3 Resource loading (images, sounds)

1.3 Acceptance criteria

1.3.1 Core flows work reliably across supported browsers

1.3.2 No major visual regression or layout break on supported viewports

1.3.3 Performance: consistent frame rates for target devices

2. Automated testing

2.1 Unit tests

2.1.1 Tools: Jest, Mocha, or vitest

2.1.2 Focus: game logic (shuffle, scoring calculations, state transitions) rather than DOM-heavy code

2.1.3 Tips: extract logic into pure functions where possible to make them testable

2.2 Integration tests

2.2.1 Tools: Testing Library (DOM Testing Library) with Jest or Vitest

2.2.2 Focus: interactions between UI components and game logic

2.2.3 Examples: clicking a card reveals it and updates game state; completing a match updates score and removes cards

2.3 End-to-end (E2E) tests

2.3.1 Tools: Playwright or Cypress

2.3.2 Scenarios to cover

2.3.2.1 Start new game, perform a sequence of moves, verify win condition and final score

2.3.2.2 Pause/resume flows

2.3.2.3 Input variations: keyboard navigation, touch gestures

2.3.3 CI: run E2E on a headless browser in CI with representative viewport sizes

2.4 Visual/regression testing

2.4.1 Tools: Percy, Playwright snapshots, or Cypress snapshot plugins

2.4.2 Baseline important screens: main menu, in-game layout, win/lose screens

3. Manual & exploratory testing

3.1 Playtesting checklist

3.1.1 End-to-end playthroughs across difficulty levels

3.1.2 Edge cases: rapid clicks, slow device behavior, switching tabs

3.1.3 Save/restore (reload mid-game) and ensure state is properly persisted or reset

3.2 Usability

3.2.1 Clear affordances for interactive elements

3.2.2 Onboarding: first-time user guidance and tutorial flows

3.3 Bug hunting heuristics

3.3.1 Fuzz inputs: random clicks, random sequences to uncover race conditions

3.3.2 Stress test: repeatedly start/stop games to expose memory leaks or event listener buildup

4. Cross-browser and device coverage

4.1 Minimum supported browsers and devices

4.1.1 Desktop: latest Chrome, Firefox, Safari, Edge

4.1.2 Mobile: iOS Safari (major versions), Chrome on Android

4.2 Responsive layout checks

4.2.1 Test key breakpoints and orientations

4.2.2 Verify touch target sizes and interaction differences

5. Accessibility (A11y)

5.1 Keyboard navigation

5.1.1 Ensure all controls are reachable and operable via keyboard

5.2 Screen reader compatibility

5.2.1 Provide ARIA labels for non-text controls

5.3 Color contrast and motion

5.3.1 Verify contrast ratios and provide reduced-motion preference support

6. Performance

6.1 Metrics to monitor

6.1.1 Frame rate consistency (target 60fps where possible)

6.1.2 Memory usage over prolonged play sessions

6.2 Tools: Lighthouse, DevTools Performance, Chrome Tracing

6.3 Optimizations to consider

6.3.1 Debounce/throttle heavy input handlers

6.3.2 Use requestAnimationFrame for animations

6.3.3 Lazy-load non-critical assets (sounds, large images)

7. Test data and environment

7.1 Test harness

7.1.1 Create fixtures for predictable RNG or seedable random function

7.1.2 Provide mock assets for CI when real assets are large or slow to load

7.2 Versioning and environment parity

7.2.1 Run tests against a staging deployment that mirrors production

8. Reporting and triage

8.1 Bug report template

8.1.1 Summary

8.1.2 Steps to reproduce

8.1.3 Expected behavior

8.1.4 Actual behavior

8.1.5 Browser, OS, device, and viewport

8.1.6 Attachments: screenshots, video, console logs

8.2 Severity and prioritization guidelines

8.2.1 Blocking: game cannot start or load

8.2.2 Major: core gameplay broken

8.2.3 Minor: visual glitches or non-critical UX issues

9. Automation in CI

9.1 Pipeline suggestions

9.1.1 Run unit tests and integration tests on every PR

9.1.2 Run E2E nightly or on merge to main for stability checks

9.1.3 Gate releases on visual regression and core E2E passing

10. Acceptance checklist (prior to release)

10.1 All critical E2E tests passing

10.2 No regressions in visual snapshots

10.3 Performance within acceptable thresholds on target devices

10.4 Accessibility basic checks passed (keyboard navigation and contrast)

Notes and recommendations

• Keep game logic decoupled from DOM to make automated testing easier.

• Prefer deterministic behaviors in tests by allowing injection of RNG seeds or mocking timers.

• Record short video playthroughs for designers and product owners to review regressions quickly.

• Use small, focused E2E scenarios rather than attempting to replicate many random play patterns in a single test.

If you want, I can convert parts of this guide into a checklist in this issue, add test examples (Jest/Playwright code snippets), or create specific automated test tickets from critical areas above.