testing

A set of Vitest testing rules. Vitest is a JavaScript and TypeScript test runner used to check that code behaves as expected.

In plain words
What is it for?
Use it when editing test or specification files, especially tests for domain packages, commands and undo, saved-document state, serialization, server routes, filesystem access, or security.
Why use it?
It makes tests predictable and keeps filesystem, HTTP, command, undo, save, and serialization checks from changing real game projects or relying on fragile snapshots.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/andvolodko/html5-game-editor/testing
Clone the repo
git clone --depth 1 https://github.com/andvolodko/html5-game-editor

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 674 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00674
Opus 5 $0.00000 $0.00337
Sonnet 5 $0.00000 $0.00135
Haiku 4.5 $0.00000 $0.00067

Measured 2d ago against content hash 0dcb747313f0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.cursor/rules/testing.mdc · 40 lines

How it starts

The opening of the file, as written. The whole thing — 40 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Testing

Stack: Vitest, colocated *.test.ts next to the unit under test. Prefer describe/it + expect. No snapshot tests unless the golden output is intentionally stable and reviewed (prefer explicit assertions).

Organization

  • Name files <module>.test.ts (e.g. commands.test.ts, project-root-guard.test.ts, router.assets.test.ts).
  • Unit-test pure domain in packages (@game-editor/scene, assets, commands, editor-core) without Pixi/Three/React.
  • Integration-test filesystem/HTTP in apps/project-server using mkdtemp + rm sandboxes and, when needed, an ephemeral createServer + fetch (see router.assets.test.ts). Never write into real game project folders under games/ from tests.
  • Keep UI React tests rare; put workflow/folder logic tests in editor-core (asset-workflows.test.ts, asset-browser-model.test.ts).

What must be covered

When changing behavior, add or update tests for:

  • Commands: execute + undo (+ redo when applicable); selection side effects (CreateSpriteCommand, SetTransform2DCommand).
  • Dirty/save: undo back to saved snapshot → clean (DocumentManager / Editor tests).
  • Serialization: JSON round-trip + parseSceneData / parseAssetDatabase; deterministic ordering where promised.
  • Schema: reject invalid shapes and invariant breaks (e.g. asset type/metadata.kind).
  • Assets: import success, duplicate naming (wild-1.png), mixed supported/unsupported batch, registry/service path — not only the texture helper in isolation.
  • Security: ProjectRootGuard traversal rejection; safe destination normalization; scene id allowlist failures when touched.
  • Coords: pure viewport math (clientPointToWorld) without bootstrapping Pixi.

Style

  • Assert observable outcomes (scene nodes, file contents, HTTP status/JSON, thrown DomainError codes), not private fields or call-order spies unless the interaction is the API (SceneRenderer fakes for viewport sync are fine).
  • Use vi.fn for ports (SceneApiClient, AssetApiClient, SceneRenderer); do not mock the filesystem layer when testing ProjectRootGuard / import services — use real temp dirs.
  • Prefer small fixtures (createEmptyScene, createTextureAssetRecord, tiny PNG buffers) over large copied project trees.
  • Do not add tests that only restate types. Do not skip failing security/path tests.

Read the full file on GitHub · 40 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 40 lines · 0 tokens per session scan A 0dcb747313f0

Subscribe to this mod's changes

testing is a cursor rule published in the GitHub repository andvolodko/html5-game-editor (5 stars, last pushed 7d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 674 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.