Writing tests

Unit and integration tests use Vitest and run from workspace directories, not the repo root.

Read a neighboring test before writing a new one — the existing suites are the specification for how we test, and they stay current in a way prose can't. Good starting points:

• packages/tldraw/src/test/SelectTool.test.ts — tool state machine assertions
• packages/tldraw/src/test/resizing.test.ts — pointer-driven interaction with handles
• packages/tldraw/src/lib/shapes/arrow/ArrowShapeUtil.test.ts — shape util plus bindings
• packages/editor/src/lib/editor/managers/ClickManager/ClickManager.test.ts — a UI-free manager
• packages/editor/src/lib/primitives/Vec.test.ts — a plain primitive

For the available TestEditor methods, read the class itself rather than a list here: packages/tldraw/src/test/TestEditor.ts.

Which workspace

• packages/editor — core primitives, geometry, managers, base editor behavior that must not depend on default shapes or UI.
• packages/tldraw — anything needing default shapes or tools, which is most integration tests.