Add ScenesUsingInTest attribute

Runtime/AssemblyInfo.cs

@@ -3,4 +3,5 @@
 
 using System.Runtime.CompilerServices;
 
+[assembly: InternalsVisibleTo("TestHelper.Editor")]
 [assembly: InternalsVisibleTo("TestHelper.Tests")]

Runtime/Attributes/ScenesUsingInTestAttribute.cs

@@ -0,0 +1,39 @@
+// Copyright (c) 2023 Koji Hasegawa.
+// This software is released under the MIT License.
+
+using System;
+using NUnit.Framework;
+
+namespace TestHelper.Attributes
+{
+    /// <summary>
+    /// Temporarily build scene files not added to "Scenes in Build" when running a test.
+    /// It has the following effects:
+    ///  - Can specify only scene name to `SceneManager.LoadScene()` method
+    ///  - Can load in `SceneManager.LoadScene()` method when running a test on a standalone player.
+    ///
+    /// This attribute is effective for the entire test run, not individual tests.
+    /// So, I recommend specifying it at the assembly level.
+    /// </summary>
+    /// <remarks>
+    /// The name is "Scene*s*" to like a "Scenes in Build".
+    /// The argument is a single string, but can attach multiple this attribute.
+    /// </remarks>
+    [AttributeUsage(AttributeTargets.Assembly | AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true)]
+    public class ScenesUsingInTestAttribute : NUnitAttribute
+    {
+        internal string ScenePath { get; private set; }
+
+        /// <summary>
+        /// Specify scene file path to temporarily build when running a test.
+        /// </summary>
+        /// <param name="scenePath">Scene path not in "Scenes in Build".
+        /// The scene file path starts with `Assets/` or `Packages/`, and ends with `.unity`.
+        /// Use `name` instead of `displayName` in package paths.
+        /// </param>
+        public ScenesUsingInTestAttribute(string scenePath)
+        {
+            ScenePath = scenePath;
+        }
+    }
+}

Tests/Runtime/Attributes/ScenesUsingInTestAttributeTest.cs

@@ -0,0 +1,40 @@
+// Copyright (c) 2023 Koji Hasegawa.
+// This software is released under the MIT License.
+
+using System.Collections;
+using System.Diagnostics.CodeAnalysis;
+using NUnit.Framework;
+using UnityEngine;
+using UnityEngine.SceneManagement;
+using UnityEngine.TestTools;
+
+namespace TestHelper.Attributes
+{
+    [TestFixture]
+    [SuppressMessage("ReSharper", "Unity.LoadSceneUnexistingScene")]
+    public class ScenesUsingInTestAttributeTest
+    {
+        [UnityTest]
+        [ScenesUsingInTest("Packages/com.nowsprinting.test-helper/Tests/Scenes/NotInScenesInBuild.unity")]
+        public IEnumerator Attach_CanLoadSceneNotIncludedBuild()
+        {
+            yield return SceneManager.LoadSceneAsync("NotInScenesInBuild");
+            var cube = GameObject.Find("CubeInNotInScenesInBuild");
+            Assert.That(cube, Is.Not.Null);
+        }
+
+        [UnityTest]
+        [ScenesUsingInTest("Packages/com.nowsprinting.test-helper/Tests/Scenes/NotInScenesInBuild.unity")]
+        [ScenesUsingInTest("Packages/com.nowsprinting.test-helper/Tests/Scenes/NotInScenesInBuild2.unity")]
+        public IEnumerator AttachMultiple_CanLoadScenesNotIncludedBuild()
+        {
+            yield return SceneManager.LoadSceneAsync("NotInScenesInBuild");
+            var cube = GameObject.Find("CubeInNotInScenesInBuild");
+            Assert.That(cube, Is.Not.Null);
+
+            yield return SceneManager.LoadSceneAsync("NotInScenesInBuild2");
+            var cube2 = GameObject.Find("CubeInNotInScenesInBuild2");
+            Assert.That(cube2, Is.Not.Null);
+        }
+    }
+}