Add a simple test to ensure spline cart is working correctly (#1002)

com.unity.cinemachine/Tests/Runtime/SplineCartTests.cs

@@ -0,0 +1,51 @@
+using System.Collections;
+using System.Collections.Generic;
+using NUnit.Framework;
+using UnityEngine;
+using UnityEngine.TestTools;
+using UnityEngine.Splines;
+using Unity.Mathematics;
+
+namespace Unity.Cinemachine.Tests
+{
+    [TestFixture]
+    public class CinemachineSplineCartTest : CinemachineRuntimeFixtureBase
+    {
+        CinemachineSplineCart m_CmSplineCart;
+        SplineContainer m_SplineContainer;
+
+        [SetUp]
+        public void Setup()
+        {
+            base.SetUp();
+
+            m_SplineContainer = CreateGameObject("Dolly Track", typeof(SplineContainer)).GetComponent<SplineContainer>();
+            m_SplineContainer.Spline = SplineFactory.CreateLinear(
+                new List<float3> { new(7, 1, -6), new(13, 1, -6), new(13, 1, 1), new(7, 1, 1) }, true);
+            m_CmSplineCart = CreateGameObject("CM cart", typeof(CinemachineSplineCart)).GetComponent<CinemachineSplineCart>();
+            m_CmSplineCart.Spline = m_SplineContainer;
+        }
+
+        [TearDown]
+        public override void TearDown()
+        {
+            base.TearDown();
+        }
+
+        [UnityTest]
+        public IEnumerator CartPositionIsCorrect()
+        {
+            m_CmSplineCart.PositionUnits = PathIndexUnit.Distance;
+            m_CmSplineCart.SplinePosition = 0;
+            yield return null;
+            UnityEngine.Assertions.Assert.AreApproximatelyEqual(
+                Vector3.Distance(m_CmSplineCart.transform.position, new Vector3(7, 1, -6)), 0, 0.1f);
+
+            m_CmSplineCart.PositionUnits = PathIndexUnit.Normalized;
+            m_CmSplineCart.SplinePosition = 1;
+            yield return null;
+            UnityEngine.Assertions.Assert.AreApproximatelyEqual(
+                Vector3.Distance(m_CmSplineCart.transform.position, new Vector3(7, 1, -6)), 0, 0.1f);
+        }
+    }
+}