Testing

Automated tests

Run from the repository root:


# Run all tests
npm test
 
# Unit tests only
npm run test:unit
 
# Integration tests only
npm run test:integration
 
# Watch mode
npm run test:watch

Manual verification

Generate sample output videos to visually verify rendering behavior:


# Run all demos
node examples/run-examples.js
 
# Run specific demos by name (partial match)
node examples/run-examples.js transitions
node examples/run-examples.js torture ken

Output goes to examples/output/. Each demo script includes a WHAT TO CHECK section describing the expected visual result at every timestamp.

Demo scripts

Script	What it covers
`demo-color-clips.js`	Flat colors, linear/radial gradients, transitions, full composition with color clips
`demo-effects.js`	All 9 effect types with smooth fade ramps
`demo-transitions.js`	Fade, wipe, slide, dissolve, fadeblack/white, short/long durations, image transitions
`demo-text-and-animations.js`	Positioning, fade, pop, pop-bounce, typewriter, scale-in, pulse, styling, word-replace
`demo-emoji-text.js`	Emoji stripping (default) and opt-in rendering via `emojiFont`, fade, fallback behavior
`demo-ken-burns.js`	All 6 presets, smart anchors, custom diagonal, slideshow with transitions
`demo-audio-mixing.js`	Volume levels, background music, standalone audio, loop, multi-source mix
`demo-watermarks.js`	Text/image watermarks, all positions, timed appearance, styled over transitions
`demo-karaoke-and-subtitles.js`	Smooth/instant karaoke, word timestamps, multiline, SRT, VTT, mixed text+karaoke
`demo-image-fit.js`	Fitting modes (blur-fill, cover, contain), Ken Burns + imageFit, mixed timelines
`demo-torture-test.js`	Kitchen sink — many clips, gaps, transitions, 6 simultaneous text animations, edge cases