Ability to remove trees in the backoffice

src/Umbraco.Tests.UnitTests/Umbraco.Web.BackOffice/CollectionBuilders/TreeCollectionBuilderTests.cs

@@ -0,0 +1,36 @@
+using System.Linq;
+using NUnit.Framework;
+using Umbraco.Cms.Core.Trees;
+using Umbraco.Cms.Web.BackOffice.Trees;
+
+namespace Umbraco.Cms.Tests.UnitTests.Umbraco.Web.BackOffice.CollectionBuilders
+{
+    public class TreeCollectionBuilderTests
+    {
+        [Test]
+        public void Adding_Tree_To_Collection_Builder()
+        {
+            var collectionBuilder = new TreeCollectionBuilder();
+            var treeDefinition = new Tree(0, "test", "test", "test", "test", TreeUse.Main, typeof(LanguageTreeController), false);
+
+            collectionBuilder.AddTree(treeDefinition);
+            var collection = collectionBuilder.CreateCollection(null);
+
+            Assert.AreEqual(1, collection.Count);
+            Assert.AreEqual(treeDefinition, collection.FirstOrDefault());
+        }
+
+        [Test]
+        public void Remove_Tree_From_Collection_Builder()
+        {
+            var collectionBuilder = new TreeCollectionBuilder();
+            var treeDefinition = new Tree(0, "test", "test", "test", "test", TreeUse.Main, typeof(LanguageTreeController), false);
+
+            collectionBuilder.AddTree(treeDefinition);
+            collectionBuilder.RemoveTreeController<LanguageTreeController>();
+            var collection = collectionBuilder.CreateCollection(null);
+
+            Assert.AreEqual(0, collection.Count);
+        }
+    }
+}

src/Umbraco.Web.BackOffice/Trees/TreeCollectionBuilder.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using Microsoft.Extensions.DependencyInjection;
 using Umbraco.Cms.Core.Composing;
 using Umbraco.Cms.Core.Trees;
@@ -56,5 +57,16 @@ public void AddTreeControllers(IEnumerable<Type> controllerTypes)
             foreach (var controllerType in controllerTypes)
                 AddTreeController(controllerType);
         }
+
+        public void RemoveTreeController<T>() => RemoveTreeController(typeof(T));
+
+        public void RemoveTreeController(Type type)
+        {
+            var tree = _trees.FirstOrDefault(it => it.TreeControllerType == type);
+            if (tree != null)
+            {
+                _trees.Remove(tree);
+            }
+        }
     }
 }