unity-tests-write

Unity Testing Skill

You are a Unity testing specialist using Unity Test Framework.

First Checks

• Read project test setup first (Packages/manifest.json, asmdef test assemblies, CI scripts, and Unity version constraints)
• Verify com.unity.test-framework version before choosing async test style (IEnumerator baseline vs async Task in newer UTF versions)
• Match existing conventions (test naming, fixture style, and coverage gates) unless the user asks to change them

Test Distribution

• EditMode Tests: Editor code, static analysis, serialization, utilities, pure logic
• PlayMode Tests: Runtime behavior, MonoBehaviour lifecycle, physics, coroutines, UI

Test Project Structure

For tests inside a project:

Tests/
├── Editor/
│   ├── <Company>.<Package>.Editor.Tests.asmdef
│   └── FeatureTests.cs
└── Runtime/
    ├── <Company>.<Package>.Tests.asmdef
    └── FeaturePlayModeTests.cs

For UPM packages where tests must NOT ship with the package, use a separate test package:

MyPackage/                    (published SDK — no tests)
├── Runtime/
├── Editor/
└── package.json

MyPackage.Tests/              (never published — internal only)
├── package.json
└── Editor/
    ├── com.company.package.tests.editor.asmdef
    └── FeatureTests.cs

UPM Package Test Setup

For tests in UPM packages to appear in Test Runner:

1. Test asmdef must have UNITY_INCLUDE_TESTS define constraint:

{
    "name": "com.company.package.tests.editor",
    "references": ["com.company.package"],
    "includePlatforms": ["Editor"],
    "overrideReferences": true,
    "precompiledReferences": ["nunit.framework.dll"],
    "autoReferenced": false,
    "defineConstraints": ["UNITY_INCLUDE_TESTS"]
}

1. Consuming project manifest.json must list the test package in testables:

{
    "dependencies": {
        "com.company.package.tests": "file:../path/to/Package.Tests"
    },
    "testables": ["com.company.package.tests"]
}

Without testables, Unity will not compile or show tests from packages.