Working (still some errors to fix) test result window.

Tests/GraphicsTests/RenderPipeline/HDRenderPipeline/PlayModeTest/ComparerShader.shader

             sampler2D _CompareTex;
             int _Mode, _MaxMode;
 
+            float _FlipV2 = 1;
+            float _CorrectGamma = 0;
+
             float _Split, _ResultSplit, _LineWidth;
 			
 			v2f vert (appdata v)
 			fixed4 frag (v2f i) : SV_Target
 			{
                 fixed4 c1 = tex2D(_MainTex, i.uv);
-                float2 uv2 = float2(i.uv.x, 1-i.uv.y);
+                float2 uv2 = i.uv;
+                if (_FlipV2 > 0) uv2.y = 1 - uv2.y;
                 fixed4 c2 = tex2D(_CompareTex, uv2);
 
                 fixed4 o = c1 - c2;
                 {
                     o.rgb = 0;
                 }
+
+                if (_CorrectGamma > 0)
+                    o.rgb = pow(o.rgb, 0.4545454545);
 
                 return o;
 			}

Tests/GraphicsTests/RenderPipeline/HDRenderPipeline/PlayModeTest/ComparerShader.shader.meta

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 ShaderImporter:
   externalObjects: {}
-  defaultTextures: []
+  defaultTextures:
+  - _MainTex: {fileID: 2800000, guid: 7d7a53c4266976c4c9934572a37ca369, type: 3}
+  - _CompareTex: {fileID: 2800000, guid: 1c8d92d1059378247a61bde39017c642, type: 3}
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Tests/Scripts/Editor/GraphicTests/Framework/GraphicTestContext.cs

         [MenuItem("Assets/Open Graphic Test Result")]
         private static void OpenGraphicTestResult()
         {
-
+            TestResultWindow.OpenWindow((SceneAsset) Selection.activeObject);
+            if (((SceneAsset) Selection.activeObject) == null) return false;
+
             List<string> scenes = new List<string>();
 
             foreach (TestFrameworkTools.TestInfo testInfo in TestFrameworkTools.CollectScenes.HDRP)

Tests/Scripts/GraphicTests/Framework/TestFrameworkTools.cs

             return true;
         }
 
+        public static Texture2D GetTemplateImage(string _templatePath)
+        {
+            string templatePath = Path.Combine(s_RootPath, "ImageTemplates");
+            templatePath = Path.Combine(templatePath, string.Format("{0}.{1}", _templatePath, "png"));
+
+            if (File.Exists(templatePath))
+            {
+                byte[] template = File.ReadAllBytes(templatePath);
+                Texture2D o = new Texture2D(4, 4);
+                return o.LoadImage(template, false) ? o : null;
+            }
+            else
+                return null;
+        }
+
+        public static Texture2D GetTemplateImage(TestInfo _testInfo)
+        {
+            return GetTemplateImage(_testInfo.templatePath);
+        }
+
+#if UNITY_EDITOR
+        public static Texture2D GetTemplateImage(UnityEngine.Object _sceneAsset, ref string path)
+        {
+            string _scenePath = AssetDatabase.GetAssetPath(_sceneAsset);
+
+            var p = new FileInfo(_scenePath);
+
+            var split = s_Path.Aggregate("", Path.Combine);
+            split = string.Format("{0}{1}", split, Path.DirectorySeparatorChar);
+            var splitPaths = p.FullName.Split(new[] { split }, StringSplitOptions.RemoveEmptyEntries);
+
+            path = splitPaths.Last();
+
+            TestInfo testInfo = new TestInfo
+            {
+                name = p.Name,
+                relativePath = p.ToString(),
+                templatePath = splitPaths.Last(),
+                threshold = 0.02f,
+                frameWait = 100,
+            };
+
+            return GetTemplateImage(testInfo);
+        }
+#endif
+
         public static class AssertFix
         {
             public static void TestWithMessages( bool? _comparison, string _fail = "Test failed", string _pass = null )

Tests/Scripts/Editor/GraphicTests/Framework/TestResultWindow.cs

+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Runtime.InteropServices;
+using UnityEngine;
+using UnityEditor;
+using UnityEngine.Experimental.Rendering;
+using UnityEditor.IMGUI.Controls;
+using UnityEngine.Events;
+
+namespace UnityEngine.Experimental.Rendering
+{
+    public class TestResultWindow : EditorWindow
+    {
+        private Texture2D templateImage;
+        private Texture2D resultImage;
+        private GUIContent diffContent;
+
+        private Material diffMaterial;
+        private float minDiff = 0.45f;
+        private float maxDiff = 0.55f;
+        private int diffStyle = 5;
+        private string[] diffStylesList = new string[] {"Red", "Green", "Blue", "RGB", "Greyscale", "Heatmap"};
+        private int[] diffStylesValues = new int[] {0, 1, 2, 3, 4, 5};
+
+        private int topBarHeight = 20;
+        private int leftBarWidth = 200;
+
+        private bool testOKOrNotRun = false;
+
+        private UnityEngine.Object sceneAsset;
+        private string templateLocation;
+        private string misMatchLocationResult;
+        private string misMatchLocationTemplate;
+
+        private GUIContent reloadContent = new GUIContent() {text = "Reload 🗘", tooltip = "Reload results."};
+        private GUIContent wipeResultContent = new GUIContent() {text = "Wipe ⎚", tooltip = "Wipe results."};
+        private GUIContent deleteTemplateContent = new GUIContent() {text = "Delete 🗑", tooltip = "Delete template."};
+
+        private TestResultTreeView testResultTreeView;
+        private TestResultViewItem testResultViewItem;
+
+        [MenuItem("Internal/GraphicTest Tools/Result Window")]
+        public static void OpenWindow()
+        {
+            OpenWindow(null);
+        }
+
+        public static void OpenWindow(SceneAsset _sceneAsset)
+        {
+            TestResultWindow window = GetWindow<TestResultWindow>();
+            window.minSize = new Vector2(800f, 800f);
+
+            window.testResultTreeView = new TestResultTreeView(new TreeViewState());
+            window.testResultTreeView.onSceneSelect += window.Reload;
+            window.Reload(_sceneAsset);
+        }
+
+        private void Reload(string name)
+        {
+            string[] guids = AssetDatabase.FindAssets(name.Remove(name.Length-6, 6));
+            if (guids.Length < 1)
+            {
+                Reload();
+            }
+            else
+            {
+                SceneAsset scene = null;
+                int i = 0;
+
+                while ((scene == null) && (i < guids.Length))
+                {
+                    string path = AssetDatabase.GUIDToAssetPath(guids[i]);
+                    scene = AssetDatabase.LoadAssetAtPath<SceneAsset>(path);
+                    i++;
+                }
+                
+                Reload(scene);
+            }
+        }
+
+        private void Reload(SceneAsset _sceneAsset = null)
+        {
+            sceneAsset = _sceneAsset;
+
+            if (templateImage != null) DestroyImmediate(templateImage);
+            string tmp = "";
+            if (sceneAsset != null ) templateImage = TestFrameworkTools.GetTemplateImage(sceneAsset, ref tmp);
+
+
+            string templatePath = Path.Combine( TestFrameworkTools.s_RootPath, "ImageTemplates");
+            templateLocation = Path.Combine(templatePath, string.Format("{0}.{1}", tmp, "png"));
+
+            if (diffContent == null) diffContent = new GUIContent();
+
+            diffContent.image = templateImage;
+
+            if (diffMaterial == null)
+            {
+                diffMaterial = new Material(Shader.Find("GraphicTests/ComparerShader"));
+                diffMaterial.SetFloat("_CorrectGamma", 1f);
+                diffMaterial.SetFloat("_FlipV2", 0f);
+            }
+
+            // Search for fail image if it exists.
+            var failedPath = Path.Combine(Directory.GetParent(Application.dataPath).ToString(), "SRP_Failed");
+            misMatchLocationResult = Path.Combine(failedPath, string.Format("{0}.unity.png", sceneAsset.name));
+            misMatchLocationTemplate = misMatchLocationResult.Insert(misMatchLocationResult.Length - 10, ".template");
+
+            if (resultImage != null && resultImage != Texture2D.blackTexture) DestroyImmediate(resultImage);
+            if (File.Exists(misMatchLocationResult))
+            {
+                resultImage = new Texture2D(templateImage.width, templateImage.height, TextureFormat.ARGB32, false);
+
+                byte[] resultBytes = File.ReadAllBytes(misMatchLocationResult);
+                resultImage.LoadImage(resultBytes);
+                testOKOrNotRun = false;
+
+                minDiff = 0.45f;
+                maxDiff = 0.55f;
+            }
+            else
+            {
+                testOKOrNotRun = true;
+                resultImage = Texture2D.blackTexture;
+
+                minDiff = 1f;
+                maxDiff = 1f;
+            }
+
+            ApplyValues();
+
+            diffMaterial.SetTexture("_CompareTex", resultImage);
+
+            testResultTreeView.Reload();
+        }
+
+        private void OnGUI()
+        {
+            // tree view
+            testResultTreeView.OnGUI(new Rect(0, 0, leftBarWidth, position.height));
+
+            if (sceneAsset == null)
+            {
+                GUI.Label(new Rect(leftBarWidth, 0, position.width - leftBarWidth, position.height), "Select a test to display");
+            }
+            else
+            {
+                // result view
+                GUILayout.BeginArea(new Rect(leftBarWidth, 0, position.width - leftBarWidth, position.height));
+                {
+                    EditorGUI.BeginChangeCheck();
+                    GUILayout.BeginHorizontal(GUILayout.Height(topBarHeight));
+                    {
+                        if (GUILayout.Button(reloadContent))
+                            Reload();
+
+                        if (GUILayout.Button(wipeResultContent))
+                        {
+                            if (File.Exists(misMatchLocationResult))
+                                File.Delete(misMatchLocationResult);
+                            if (File.Exists(misMatchLocationTemplate))
+                                File.Delete(misMatchLocationTemplate);
+                        }
+
+                        if (GUILayout.Button(deleteTemplateContent))
+                        {
+                            if (File.Exists(templateLocation))
+                            {
+                                File.Delete(templateLocation);
+                                AssetDatabase.Refresh();
+                            }
+                        }
+
+                        GUILayout.FlexibleSpace();
+                        if (testOKOrNotRun)
+                        {
+                            GUI.enabled = false;
+                            GUI.color = Color.green;
+                            GUILayout.Label("Test OK or not run.");
+                            GUI.color = Color.white;
+                            GUILayout.FlexibleSpace();
+                        }
+
+                        GUILayout.Label("Diff. type: ");
+                        diffStyle = EditorGUILayout.IntPopup(diffStyle, diffStylesList, diffStylesValues,
+                            GUILayout.Width(200f));
+                    }
+                    GUILayout.EndHorizontal();
+
+                    EditorGUILayout.MinMaxSlider(ref minDiff, ref maxDiff, 0f, 1f, GUILayout.Height(topBarHeight));
+
+                    if (EditorGUI.EndChangeCheck()) ApplyValues();
+                }
+                GUILayout.EndArea();
+
+                Rect textureRect = new Rect(leftBarWidth, topBarHeight * 2, position.width - leftBarWidth,
+                    position.height - topBarHeight * 2);
+                EditorGUI.DrawPreviewTexture(textureRect, templateImage, diffMaterial, ScaleMode.ScaleToFit, 0, 0);
+            }
+        }
+
+        private void ApplyValues()
+        {
+            float resultSplit = maxDiff - minDiff;
+            float split = (minDiff + maxDiff) / 2f;
+            split = (split - 0.5f * resultSplit) / (1 - resultSplit); //  inverse the lerp used in the shader
+
+            diffMaterial.SetFloat("_Split", split);
+            diffMaterial.SetFloat("_ResultSplit", resultSplit);
+            diffMaterial.SetInt("_Mode", diffStyle);
+        }
+
+        public class TestResultTreeView : TreeView
+        {
+            public delegate void OnSceneSelect(string name);
+            public OnSceneSelect onSceneSelect;
+
+            delegate void OnNewSceneSelect(SceneAsset newScene);
+
+            public TestResultTreeView(TreeViewState state) : base(state)
+            {
+                Reload();
+            }
+
+            protected override TreeViewItem BuildRoot()
+            {
+                TreeViewItem root = new TreeViewItem(0, -1, "Root");
+
+                int nextID = 1;
+
+                TreeViewItem hdrpParent = new TreeViewItem(nextID, 0, "HDRP");
+                ++nextID;
+                root.AddChild(hdrpParent);
+                TreeViewItem lwrpParent = new TreeViewItem(nextID, 0, "LWRP");
+                ++nextID;
+                root.AddChild(lwrpParent);
+
+                Dictionary<string, TreeViewItem> hdrpFolders = new Dictionary<string, TreeViewItem>();
+
+                foreach (TestFrameworkTools.TestInfo info in TestFrameworkTools.CollectScenes.HDRP)
+                {
+                    TreeViewItem parent = hdrpParent;
+
+                    string folder = Path.GetDirectoryName( info.templatePath ).Split("\\"[0]).Last();
+                    if (hdrpFolders.ContainsKey(folder))
+                    {
+                        parent = hdrpFolders[folder];
+                    }
+                    else
+                    {
+                        parent = new TreeViewItem(nextID, 0, folder);
+                        nextID++;
+
+                        hdrpParent.AddChild(parent);
+                        hdrpFolders.Add(folder, parent);
+                    }
+
+                    var prjRelativeGraphsPath = TestFrameworkTools.s_Path.Aggregate(TestFrameworkTools.s_RootPath, Path.Combine);
+                    var filePath = Path.Combine(prjRelativeGraphsPath, info.relativePath);
+
+                    filePath = filePath.Replace(Application.dataPath, "");
+
+                    SceneAsset sceneObject = AssetDatabase.LoadAssetAtPath<SceneAsset>(filePath);
+
+                    TestResultViewItem item = new TestResultViewItem(nextID, 0, info.name, sceneObject);
+                    nextID++;
+                    parent.AddChild(item);
+                }
+
+                Dictionary<string, TreeViewItem> lwrpFolders = new Dictionary<string, TreeViewItem>();
+
+                foreach (TestFrameworkTools.TestInfo info in TestFrameworkTools.CollectScenes.LWRP)
+                {
+                    TreeViewItem parent = lwrpParent;
+
+                    string folder = Path.GetDirectoryName( info.templatePath ).Split("\\"[0]).Last();
+                    if (lwrpFolders.ContainsKey(folder))
+                    {
+                        parent = lwrpFolders[folder];
+                    }
+                    else
+                    {
+                        parent = new TreeViewItem(nextID, 0, folder);
+                        nextID++;
+
+                        lwrpParent.AddChild(parent);
+                        lwrpFolders.Add(folder, parent);
+                    }
+
+                    var prjRelativeGraphsPath = TestFrameworkTools.s_Path.Aggregate(TestFrameworkTools.s_RootPath, Path.Combine);
+                    var filePath = Path.Combine(prjRelativeGraphsPath, info.relativePath);
+
+                    filePath = filePath.Replace(Application.dataPath, "");
+
+                    SceneAsset sceneObject = AssetDatabase.LoadAssetAtPath<SceneAsset>(filePath);
+
+                    TestResultViewItem item = new TestResultViewItem(nextID, 0, info.name, sceneObject);
+                    nextID++;
+                    parent.AddChild(item);
+                }
+
+                SetupDepthsFromParentsAndChildren(root);
+
+                return root;
+            }
+
+            protected override bool CanMultiSelect(TreeViewItem item) { return false; }
+
+            protected override void SelectionChanged(IList<int> selectedIds)
+            {
+                if (selectedIds.Count < 1 ) return;
+
+                TreeViewItem item = FindItem(selectedIds[0], rootItem);
+
+                if ( item.hasChildren ) return; // not a scene (final) item
+
+                //TestResultViewItem testItem = (TestResultViewItem)item;
+
+                //if (testItem!=null) Debug.Log(item.displayName+" : "+testItem.sceneObject);
+
+                onSceneSelect(item.displayName);
+            }
+        }
+
+        [Serializable]
+        public class TestResultViewItem : TreeViewItem
+        {
+            public SceneAsset sceneObject;
+
+            public TestResultViewItem(int id, int depth, string displayName, SceneAsset sceneObject)
+            {
+                this.id = id;
+                this.depth = depth;
+                this.displayName = displayName;
+                this.sceneObject = sceneObject;
+            }
+        }
+    }
+}

Tests/Scripts/Editor/GraphicTests/Framework/TestResultWindow.cs.meta

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