Unity Testing

Unity Test Framework

Test types

Default to EditMode; reserve PlayMode for things that genuinely need the engine loop.

Asmdef setup

Assets/Tests/EditMode.asmdef     (Test Assemblies + Editor-only references)
Assets/Tests/PlayMode.asmdef     (Test Assemblies + runtime + editor)

Add Test Assemblies flag in asmdef Inspector.

EditMode test

using NUnit.Framework;

public class HealthTests {
    [Test] public void TakeDamage_ReducesHealth() {
        var h = new Health(100);
        h.TakeDamage(30);
        Assert.AreEqual(70, h.Current);
    }

    [TestCase(100, 200, 0)]
    [TestCase(100, 50, 50)]
    public void Damage_ClampsAtZero(int max, int dmg, int expected) {
        var h = new Health(max);
        h.TakeDamage(dmg);
        Assert.AreEqual(expected, h.Current);
    }
}

PlayMode test ([UnityTest])

using UnityEngine.TestTools;
using System.Collections;
using UnityEngine;

public class JumpTests {
    [UnityTest] public IEnumerator Jump_LeavesGroundForOneSecond() {
        var go = new GameObject("Player", typeof(Rigidbody), typeof(PlayerJump));
        go.transform.position = Vector3.up;
        var jump = go.GetComponent<PlayerJump>();
        jump.DoJump();
        yield return new WaitForSeconds(1f);
        Assert.IsTrue(go.transform.position.y > 1f);
        Object.Destroy(go);
    }
}

yield return null → next frame; WaitForSeconds, WaitForFixedUpdate, WaitUntil(() => …).

Mocking time / input

• Time: inject an ITime abstraction that wraps Time.deltaTime; in tests pass a fake.
• Input: don't read _action.ReadValue directly in test target — pass values via method, or use InputTestFixture for low-level input simulation.

Performance tests (Unity.PerformanceTesting package)

[Test, Performance]
public void Pathfinder_PerfBaseline() {
    Measure.Method(() => Pathfinder.FindPath(start, end, grid))
           .WarmupCount(10)
           .MeasurementCount(50)
           .Run();
}

Reports captured to PerformanceTests folder; CI baselines via Performance Test Reporter.

CI integration

Unity -batchmode -projectPath . \
  -runTests -testPlatform EditMode \
  -testResults Tests/edit-results.xml \
  -logFile - || exit 1

Unity -batchmode -projectPath . \
  -runTests -testPlatform PlayMode \
  -testResults Tests/play-results.xml \
  -logFile - || exit 1

Convert *.xml (NUnit format) to JUnit for GitHub/GitLab reports.

Anti-patterns

Production checklist

• Test asmdefs flagged Test Assemblies
• EditMode covers all POCO logic
• PlayMode reserved for engine-dependent behaviour
• Performance baselines tracked in CI
• Tests run in CI on every PR
• Random seeds reproducible (fix Random.InitState(seed) in [SetUp])