starts writing tests

src/Umbraco.Tests/PublishedContent/NuCacheChildrenTests.cs

@@ -213,22 +213,24 @@ namespace Umbraco.Tests.PublishedContent
             var level = path.Count(x => x == ',');
             var now = DateTime.Now;
 
+            var contentData = new ContentData
+            {
+                Name = "N" + id,
+                Published = true,
+                TemplateId = 0,
+                VersionId = 1,
+                VersionDate = now,
+                WriterId = 0,
+                Properties = new Dictionary<string, PropertyData[]>(),
+                CultureInfos = new Dictionary<string, CultureVariation>()
+            };
+
             return new ContentNodeKit
             {
                 ContentTypeId = _contentTypeInvariant.Id,
                 Node = new ContentNode(id, Guid.NewGuid(), level, path, sortOrder, parentId, DateTime.Now, 0),
                 DraftData = null,
-                PublishedData = new ContentData
-                {
-                    Name = "N" + id,
-                    Published = true,
-                    TemplateId = 0,
-                    VersionId = 1,
-                    VersionDate = now,
-                    WriterId = 0,
-                    Properties = new Dictionary<string, PropertyData[]>(),
-                    CultureInfos = new Dictionary<string, CultureVariation>()
-                }
+                PublishedData = contentData
             };
         }
 
@@ -333,7 +335,7 @@ namespace Umbraco.Tests.PublishedContent
                     CultureInfos = GetCultureInfos(id, now)
                 };
 
-                var withDraft = id%2==0;
+                var withDraft = id % 2 == 0;
                 var withPublished = !withDraft;
 
                 return new ContentNodeKit
@@ -1063,6 +1065,88 @@ namespace Umbraco.Tests.PublishedContent
             AssertLinkedNode(child3.contentNode, 1, 2, -1, -1, -1);
         }
 
+        /// <summary>
+        /// This addresses issue: https://github.com/umbraco/Umbraco-CMS/issues/6698
+        /// </summary>
+        /// <remarks>
+        /// This test mimics if someone were to:
+        ///  1) Unpublish a "middle child"
+        ///  2) Save and publish it
+        ///  3) Publish it with descendants
+        ///  4) Repeat steps 2 and 3
+        ///  
+        /// Which has caused an exception. To replicate this test:
+        ///  1) RefreshBranch with kits for a branch where the top most node is unpublished
+        ///  2) RefreshBranch with kits for the branch where the top most node is published
+        ///  3) RefreshBranch with kits for the branch where the top most node is published
+        ///  4) RefreshBranch with kits for the branch where the top most node is published
+        ///  5) RefreshBranch with kits for the branch where the top most node is published
+        /// </remarks>
+        [Test]
+        public void Refresh_Branch_With_Alternating_Publish_Flags()
+        {
+            // NOTE: these tests are not using real scopes, in which case a Scope does not control
+            // how the snapshots generations work. We are forcing new snapshot generations manually.
+
+            IEnumerable<ContentNodeKit> GetKits()
+            {
+                var paths = new Dictionary<int, string> { { -1, "-1" } };
+
+                //root
+                yield return CreateInvariantKit(1, -1, 1, paths);
+
+                //children
+                yield return CreateInvariantKit(2, 1, 1, paths);
+                yield return CreateInvariantKit(3, 1, 2, paths); //middle child
+                yield return CreateInvariantKit(4, 1, 3, paths);
+            }
+
+            //init with all published
+            Init(GetKits());
+
+            var snapshotService = (PublishedSnapshotService)_snapshotService;
+            var contentStore = snapshotService.GetContentStore();
+
+            var rootKit = _source.Kits[1].Clone();
+
+            void ChangePublishFlagOfRoot(bool published, int assertGen)
+            {
+                //This will set a flag to force creating a new Gen next time the store is locked (i.e. In Notify)
+                contentStore.CreateSnapshot();
+
+                Assert.IsFalse(contentStore.Test.NextGen);
+
+                //Change the root publish flag
+                var kit = rootKit.Clone();
+                kit.DraftData = published ? null : kit.PublishedData;
+                kit.PublishedData = published? kit.PublishedData : null;
+                _source.Kits[1] = kit;
+
+                _snapshotService.Notify(new[]
+                {
+                    new ContentCacheRefresher.JsonPayload(1, Guid.Empty, TreeChangeTypes.RefreshBranch)
+                }, out _, out _);
+
+                Assert.AreEqual(assertGen, contentStore.Test.LiveGen);
+                Assert.IsTrue(contentStore.Test.NextGen);
+            }
+
+            //unpublish the root
+            ChangePublishFlagOfRoot(false, 2);
+
+            //publish the root
+            ChangePublishFlagOfRoot(true, 3);
+
+            //publish root + descendants
+            ChangePublishFlagOfRoot(true, 4);
+
+            //publish the root
+            ChangePublishFlagOfRoot(true, 5);
+
+            //publish root + descendants
+            ChangePublishFlagOfRoot(true, 6); //TODO: This should fail, need to figure out what the diff is between this and a website
+        }
+
         [Test]
         public void Refresh_Branch_Ensures_Linked_List()
         {