Because clients receive all their dependencies from the outside, instead of fetching them from singletons or using methods like There’s no need to create test scenes or prefabs and configure them using the Inspector. You can create clients directly in code, pass them fake objects, and then verify that they behave as expected.<\/p>\n This works in both Edit Mode and Play Mode tests.<\/p>\n Unity’s Test Framework<\/a> requires that unit tests are placed inside their own assembly definition<\/a>. You can create one using the Test Runner window (Window > General > Test Runner<\/strong>).<\/p>\n Your test assembly should have references to the following assemblies:<\/p>\n <\/p>\n See Referencing Init(args) Assemblies<\/a> for more information.<\/p>\n Let’s say you have a component that triggers an event when it is collected:<\/p>\n To test it, first create a simple fake implementation of Then pass it to the client using The Prefabs can be initialized in the same way using You can also use new GameObject<T…><\/a> to create a new GameObject and initialize a client in a single line:<\/p>\n This also makes it easy to create a GameObject with multiple components. For example, here a If a client depends on another component on the same GameObject, you can use the In Edit Mode tests Unity doesn’t execute event functions like Simply wrap the GameObject containing your client inside a Things to know about Here’s an example of a test that simulates two objects colliding:<\/p>\n If a plain old C# object is attached to a GameObject using a Wrapper<\/a>, you can test it without creating any GameObjects at all. Just pass all its dependencies to it through its constructor:<\/p>\n Sometimes it is not practical to pass every dependency to clients individually. For example:<\/p>\n In such cases you can replace global services with test doubles for the duration of the test using the Service API<\/a>:<\/p>\n Note that One pattern that can sometimes be useful is to create a base class that replaces commonly used services with test doubles before each test, and restores the originals after it:<\/p>\nGetComponent<\/code> and FindAnyObjectByType<\/code>, it is easy to swap out any of them with test doubles during unit tests.<\/p>\nSetting Up A Test Assembly<\/h1>\n
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AddComponent<\/code>, Instantiate<\/code>, new GameObject<T...><\/code> and the Service API<\/a>.<\/li>\nTestable<\/code> helper class in Edit Mode tests.<\/li>\nPassing Test Doubles With AddComponent<\/h1>\n
using Sisus.Init;\r\nusing UnityEngine;\r\n\r\npublic class Collectable : MonoBehaviour<IEventTrigger>\r\n{\r\n IEventTrigger onCollected;\r\n\r\n protected override void Init(IEventTrigger onCollected) => this.onCollected = onCollected;\r\n\r\n public void Collect()\r\n {\r\n onCollected.Trigger();\r\n gameObject.SetActive(false);\r\n }\r\n}<\/pre>\nIEventTrigger<\/code> that keeps track of whether it has been triggered:<\/p>\npublic class FakeEvent : IEventTrigger\r\n{\r\n public bool HasBeenTriggered { get; private set; }\r\n public void Trigger() => HasBeenTriggered = true;\r\n}<\/pre>\nAddComponent<\/code>:<\/p>\nusing NUnit.Framework;\r\nusing Sisus.Init;\r\nusing UnityEngine;\r\n\r\npublic class TestCollectable\r\n{\r\n [Test]\r\n public void Collect_Triggers_Event()\r\n {\r\n var gameObject = new GameObject();\r\n var onCollected = new FakeEvent();\r\n var collectable = gameObject.AddComponent<Collectable, IEventTrigger>(onCollected);\r\n\r\n collectable.Collect();\r\n\r\n Assert.IsTrue(onCollected.HasBeenTriggered);\r\n\r\n Object.DestroyImmediate(gameObject);\r\n }\r\n}<\/pre>\nInit<\/code> method of the client gets executed before AddComponent<\/code> returns, so the client is immediately ready to be tested. This is the case even if the GameObject is inactive, and even in Edit Mode tests.<\/p>\nInstantiate<\/code>:<\/p>\nvar collectable = collectablePrefab.Instantiate(onCollected);<\/pre>\n
Creating Clients With new GameObject<T…><\/h1>\n
var collectable = new GameObject<Collectable>().Init(onCollected);<\/pre>\n
Killable<\/code> component is added together with a BoxCollider<\/code>, and initialized using Init1<\/code> (the 1<\/strong> indicating that the arguments are for the first component):<\/p>\nvar killable = new GameObject<Killable, BoxCollider>().Init1((IEventTrigger)onKilled);<\/pre>\n
Second.Component<\/code> token to pass it the second added component:<\/p>\nvar player = new GameObject<Player, Camera>().Init1(inputManager, Second.Component);<\/pre>\n
Executing Event Functions In Edit Mode<\/h1>\n
Awake<\/code>, Start<\/code> and Update<\/code> automatically. You can use the Testable<\/code> class from the Sisus.Init.Testing<\/code> namespace to execute them manually.<\/p>\nTestable<\/code>, and then call the event functions you want to execute on it:<\/p>\nusing NUnit.Framework;\r\nusing Sisus.Init;\r\nusing Sisus.Init.Testing;\r\nusing UnityEngine;\r\n\r\npublic class TestMovable\r\n{\r\n [Test]\r\n public void Can_Move_Right()\r\n {\r\n var settings = new FakeMoveSettings { MoveSpeed = 1f };\r\n var level = new FakeLevel { Bounds = new RectInt(0, 0, 3, 1) };\r\n var timeProvider = new TestTimeProvider { DeltaTime = 1f };\r\n var movable = new GameObject<Movable>().Init(settings, level, timeProvider);\r\n using var testable = new Testable(movable.gameObject);\r\n\r\n movable.MoveDirection = Vector2.right;\r\n testable.Update();\r\n\r\n Assert.AreEqual(new Vector2(1f, 0f), movable.Position);\r\n }\r\n}<\/pre>\nTestable<\/code>:<\/p>\n\n
Testable<\/code> is created, it executes Awake<\/code>, OnEnable<\/code> and Start<\/code> on all components on the GameObject. You can turn this off by passing false<\/code> as the second constructor argument.<\/li>\nUpdate<\/code> and FixedUpdate<\/code> optionally accept the number of times to execute them, e.g. testable.Update(3)<\/code>.<\/li>\ntestable.OnTriggerEnter(collider)<\/code>.<\/li>\nRaiseEvent(nameof(MyClient.EventName))<\/code>.<\/li>\nDestroy<\/code> executes OnDisable<\/code> and OnDestroy<\/code> and then destroys the GameObject. A using<\/code> statement can be used to do this automatically at the end of the test.<\/li>\n<\/ul>\n[Test]\r\npublic void OnTriggerEnter_With_Deadly_Object_Sets_GameObject_Inactive()\r\n{\r\n var killable = new GameObject<Killable, BoxCollider>().Init1((IEventTrigger)new FakeEvent());\r\n using var testable = new Testable(killable.gameObject);\r\n (FakeDeadly deadly, BoxCollider collider) deadly = new GameObject<FakeDeadly, BoxCollider>();\r\n\r\n testable.OnTriggerEnter(deadly.collider);\r\n\r\n Assert.IsFalse(killable.gameObject.activeSelf);\r\n\r\n Object.DestroyImmediate(deadly.collider.gameObject);\r\n}<\/pre>\nTesting Plain Old C# Objects<\/h1>\n
var spawner = new Spawner(settings, new FakeTrackable(), new FakeLevel(), timeProvider, gameObjectBuilder);<\/pre>\n
Replacing Global Services<\/h1>\n
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Any<TValue><\/code> field or inside a method body using the Service API instead of receiving it as an Init argument.<\/li>\n<\/ul>\n[SetUp]\r\npublic void SetUp() => Service.Set<ILogger>(testLogger);\r\n\r\n[TearDown]\r\npublic void TearDown() => Service.Unset<ILogger>(testLogger);<\/pre>\n
Service.Set<\/code> replaces the existing global service of the same type, and Service.Unset<\/code> does not bring it back. If you want to restore the original service after the test, you can store a reference to it and set it back afterwards:<\/p>\npublic readonly struct ScopedService<T> : IDisposable\r\n{\r\n readonly T previous;\r\n\r\n public ScopedService(T service)\r\n {\r\n previous = Service<T>.Instance;\r\n Service.Set(service);\r\n }\r\n\r\n public void Dispose()\r\n {\r\n Service.Unset<T>();\r\n if(previous is not null)\r\n {\r\n Service.Set(previous);\r\n }\r\n }\r\n}<\/pre>\npublic abstract class UnitTests\r\n{\r\n ScopedService<ILogger> logger;\r\n ScopedService<ITimeProvider> timeProvider;\r\n\r\n protected TestLogger Logger { get; } = new();\r\n protected TestTimeProvider TimeProvider { get; } = new();\r\n\r\n [SetUp]\r\n public void Setup()\r\n {\r\n logger = new(Logger);\r\n timeProvider = new(TimeProvider);\r\n OnSetup();\r\n }\r\n\r\n [TearDown]\r\n public void TearDown()\r\n {\r\n OnTearDown();\r\n logger.Dispose();\r\n timeProvider.Dispose();\r\n }\r\n\r\n protected virtual void OnSetup() { }\r\n protected virtual void OnTearDown() { }\r\n}<\/pre>\nTips<\/h1>\n
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ILogger<\/code>, ITimeProvider<\/code> or IInputManager<\/code> instead of concrete types can be easier to test, because a simple fake class can be passed to them instead of the real implementation.<\/li>\nTime.deltaTime<\/code> and Input.GetAxis<\/code> can’t be replaced in tests. If you access them through a service instead (e.g. ITimeProvider<\/code>), you can fully control them during tests.<\/li>\nNUnit.Framework<\/code> and Sisus.Init<\/code> contain a type named Is<\/code>. If you get an ambiguity error when using Assert.That(x, Is.EqualTo(y))<\/code>, you can add using Is = NUnit.Framework.Is;<\/code> to the top of the file.<\/li>\n<\/ul>\nMore Examples<\/h1>\n