Markdown Viewer is a static browser application with a Neutralino desktop wrapper. The shared test suite uses Playwright to exercise editing, preview rendering, tabs, import/export, sharing, responsive layout, browser storage, and accessibility behavior.

• Node.js 22 (see .nvmrc)
• npm

Install the locked dependencies and Playwright browsers once:

npm ci
npm run test:install

Use npx playwright install --with-deps instead on Linux when system browser dependencies are not already installed.

npm run build                  # static assets, JSON, HTML IDs/references, and JavaScript syntax
npm run test:e2e               # complete Chromium suite
npm test                       # static validation plus the complete Chromium suite
npm run test:e2e:smoke         # fast Chromium smoke suite
npm run test:e2e:cross-browser # smoke suite in Chromium, Firefox, and WebKit

Run one file or a matching test:

npm run test:e2e -- tests/e2e/editor.spec.js
npm run test:e2e -- --grep "workspace backup"

For interactive debugging:

npm run test:e2e:ui
npm run test:e2e:headed
npm run test:e2e:report

The Playwright configuration starts a cross-platform Node static server automatically. Core browser libraries are fulfilled from locked npm packages during tests. External renderer, GitHub, and Live Share calls are mocked in the specifications that exercise those integrations.

• Static validation and application startup
• Markdown editing, GFM rendering, formatting, tabs, and file import
• Mermaid, PlantUML, Graphviz/DOT, D2, Vega-Lite, WaveDrom, Markmap, math, ABC notation, maps, and STL surfaces
• Share Snapshot and locally mocked Live Share access behavior
• Markdown, HTML, PNG, and browser-print PDF export paths
• Workspace storage, migration, backup/restore, Private mode, and responsive behavior
• Explorer, toolbar, dialogs, keyboard interaction, accessible names, and focus management

Live Share tests use a local WebSocket/Yjs substitute and do not replace a Cloudflare Durable Object integration test. Production CDN availability and deployed Cloudflare bindings should be monitored separately from the deterministic local suite.

Before changing application behavior, run the focused specification for the affected area. Before opening a pull request, run:

npm test
npm run test:e2e:cross-browser

Tests must be isolated, deterministic, and runnable locally on Windows, macOS, and Linux. Prefer user-facing roles and labels over DOM implementation selectors. Store fixtures under tests/fixtures/; never write artifacts to user-specific paths. Playwright captures screenshots and videos on failure under the ignored test-results/ directory and writes its local HTML report to playwright-report/.

This repository intentionally does not run the Playwright suite in GitHub Actions. Contributors are responsible for running the checks locally before requesting review or merging a change.