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.cursor/rules/testing.mdc

Cursor testing rule for Unity

A Cursor `.mdc` rule can attach only when you touch tests. This variant keeps testing policy out of the always-on project rule so day-to-day edits stay quieter. This copy is written for a Unity project. This repository is a Unity project in C#. Compose behavior with components, expose inspector values with SerializeField, and keep the Unity API on the main thread.

The example uses a balanced, readable style, pragmatic tests, and comments only where the intent is not obvious. Open the generator to make the agent stricter, switch to test-first, quiet the comments, or pick a different file.

The example assumes Unity LTS and C# MonoBehaviours. It does not assume Netcode, Addressables, or a particular input system. If the project uses the new Input System or a custom framework, follow that.

Customize in the generatorBrowse the library

Example file

Balanced strictness, readable style, pragmatic tests. Download name: testing.mdc

---
description: "Testing rules for a Unity repository"
globs: "**/*Tests.cs"
alwaysApply: false
---

# Testing rules

Attach these rules when editing tests in this Unity repository.
The always-on project rule still lives in `.cursor/rules/project.mdc`. This file does not repeat it.

## Stack

This repository is a Unity project in C#. Compose behavior with components, expose inspector values with SerializeField, and keep the Unity API on the main thread.

## Commands

- Open: `Open the project in the Unity Editor for this version`
- Tests: `Window > General > Test Runner`
- Play: `Enter Play Mode from the scene you changed`

Use the script the repo already defines when it differs from the command above.

## Testing

Add or update tests when behavior changes.

Use the Unity Test Framework. Prefer an Edit Mode test for pure C# and a Play Mode test only when you need the engine.

## Done when

- The requested behavior works.
- The script compiles in the Editor, and you ran the Test Runner or Play Mode for the scene you touched.
- The diff stays inside the task.
- You list anything you could not run.

Add it to the project

  1. 01

    Copy a starting file

    Copy the example Cursor testing rule on this page, or open the generator if you want different testing, strictness, or comment rules.

  2. 02

    Save it at .cursor/rules/testing.mdc

    Save it at `.cursor/rules/testing.mdc` in the Unity repo, next to the always-on project rule. Leave `alwaysApply` false so it only joins test edits.

  3. 03

    Start a fresh agent session

    Rules files are read when a session starts. A chat that is already open may still be using the old instructions.

  4. 04

    Give it one small task

    Ask for one change a Unity agent often gets wrong, such as a component that moves work out of Update when it only needs to react to an event. If it ignores the file, confirm the path and start a new session.

Questions about this file

Where do I put Cursor testing rule in a Unity repo?

Save it at `.cursor/rules/testing.mdc` in the Unity repo, next to the always-on project rule. Leave `alwaysApply` false so it only joins test edits.

Which tools read this Cursor testing rule?

Cursor loads `.cursor/rules/testing.mdc` when a file matches its globs. It does not replace `project.mdc`. Keep the always-on rule for stack conventions.

What does the Unity example assume?

The example assumes Unity LTS and C# MonoBehaviours. It does not assume Netcode, Addressables, or a particular input system. If the project uses the new Input System or a custom framework, follow that.

Does VibeSpell upload my repository?

No. Recipe pages are static, and the generator builds the file in your browser from the options you pick. Your source code never leaves the machine.

Other files for Unity

Cursor testing rule for other stacks