diff --git a/tests/GameUtils.Tests/Types/Collections/QuadTreeTests.cs b/tests/GameUtils.Tests/Types/Collections/QuadTreeTests.cs
index f908f02..23e53d2 100644
--- a/tests/GameUtils.Tests/Types/Collections/QuadTreeTests.cs
+++ b/tests/GameUtils.Tests/Types/Collections/QuadTreeTests.cs
@@ -12,6 +12,137 @@ public class QuadTreeTests
 {
     private static AABB DefaultBounds => new AABB(new Vector2(0, 0), new Vector2(100, 100));
 
+    // --- Tests from branch test/quadtree-insert-tests ---
+
+    [TestMethod]
+    public void Insert_OutsideBounds_ReturnsFalse()
+    {
+        var bounds = new AABB(new Vector2(0, 0), new Vector2(10, 10));
+        var quadTree = new QuadTree<string>(bounds);
+
+        bool result = quadTree.Insert("item1", new Vector2(15, 15));
+
+        Assert.IsFalse(result);
+        Assert.AreEqual(0, quadTree.Query(bounds).Count());
+    }
+
+    [TestMethod]
+    public void Insert_InsideBounds_ReturnsTrueAndQueryable()
+    {
+        var bounds = new AABB(new Vector2(0, 0), new Vector2(10, 10));
+        var quadTree = new QuadTree<string>(bounds);
+
+        bool result = quadTree.Insert("item1", new Vector2(5, 5));
+
+        Assert.IsTrue(result);
+        var items = quadTree.Query(bounds).ToList();
+        Assert.AreEqual(1, items.Count);
+        Assert.AreEqual("item1", items[0]);
+    }
+
+    [TestMethod]
+    public void Insert_AtBoundaries_ReturnsTrue()
+    {
+        var bounds = new AABB(new Vector2(0, 0), new Vector2(10, 10));
+        var quadTree = new QuadTree<string>(bounds);
+
+        Assert.IsTrue(quadTree.Insert("min", new Vector2(0, 0)));
+        Assert.IsTrue(quadTree.Insert("max", new Vector2(10, 10)));
+        Assert.AreEqual(2, quadTree.Query(bounds).Count());
+    }
+
+    [TestMethod]
+    public void Insert_ExceedingCapacity_SubdividesAndDistributesItems()
+    {
+        var bounds = new AABB(new Vector2(0, 0), new Vector2(100, 100));
+        var quadTree = new QuadTree<string>(bounds, capacity: 4);
+
+        quadTree.Insert("TL", new Vector2(25, 25));
+        quadTree.Insert("TR", new Vector2(75, 25));
+        quadTree.Insert("BL", new Vector2(25, 75));
+        quadTree.Insert("BR", new Vector2(75, 75));
+
+        quadTree.Insert("TL2", new Vector2(10, 10));
+
+        var allItems = quadTree.Query(bounds).ToList();
+        Assert.AreEqual(5, allItems.Count);
+
+        var tlRegion = new AABB(new Vector2(0, 0), new Vector2(50, 50));
+        var tlItems = quadTree.Query(tlRegion).ToList();
+        Assert.IsTrue(tlItems.Contains("TL"));
+        Assert.IsTrue(tlItems.Contains("TL2"));
+        Assert.AreEqual(2, tlItems.Count);
+    }
+
+    [TestMethod]
+    public void Insert_ExceedingMaxDepth_StopsSubdividingAndStoresInLeaf()
+    {
+        var bounds = new AABB(new Vector2(0, 0), new Vector2(10, 10));
+        var quadTree = new QuadTree<string>(bounds, capacity: 1);
+
+        for (int i = 0; i < 20; i++)
+        {
+            Assert.IsTrue(quadTree.Insert($"item{i}", new Vector2(5, 5)));
+        }
+
+        Assert.AreEqual(20, quadTree.Query(bounds).Count());
+    }
+
+    [TestMethod]
+    public void Insert_MultipleItemsAtSamePosition_ReturnsTrue()
+    {
+        var bounds = new AABB(new Vector2(0, 0), new Vector2(10, 10));
+        var quadTree = new QuadTree<string>(bounds);
+
+        Assert.IsTrue(quadTree.Insert("item1", new Vector2(5, 5)));
+        Assert.IsTrue(quadTree.Insert("item2", new Vector2(5, 5)));
+        Assert.AreEqual(2, quadTree.Query(bounds).Count());
+    }
+
+    [TestMethod]
+    public void Remove_InsertedItem_ReturnsTrueAndRemovesItem()
+    {
+        var bounds = new AABB(new Vector2(0, 0), new Vector2(10, 10));
+        var quadTree = new QuadTree<string>(bounds);
+
+        quadTree.Insert("item1", new Vector2(5, 5));
+        bool removed = quadTree.Remove("item1", new Vector2(5, 5));
+
+        Assert.IsTrue(removed);
+        Assert.AreEqual(0, quadTree.Query(bounds).Count());
+    }
+
+    [TestMethod]
+    public void Remove_SubdividedTreeItem_ReturnsTrueAndRemovesItem()
+    {
+        var bounds = new AABB(new Vector2(0, 0), new Vector2(100, 100));
+        var quadTree = new QuadTree<string>(bounds, capacity: 2);
+
+        quadTree.Insert("A", new Vector2(10, 10));
+        quadTree.Insert("B", new Vector2(20, 20));
+        quadTree.Insert("C", new Vector2(80, 80));
+
+        Assert.IsTrue(quadTree.Remove("C", new Vector2(80, 80)));
+        Assert.AreEqual(2, quadTree.Query(bounds).Count());
+    }
+
+    [TestMethod]
+    public void Clear_RemovesAllItems()
+    {
+        var bounds = new AABB(new Vector2(0, 0), new Vector2(100, 100));
+        var quadTree = new QuadTree<string>(bounds, capacity: 2);
+
+        quadTree.Insert("A", new Vector2(10, 10));
+        quadTree.Insert("B", new Vector2(20, 20));
+        quadTree.Insert("C", new Vector2(80, 80));
+
+        quadTree.Clear();
+
+        Assert.AreEqual(0, quadTree.Query(bounds).Count());
+    }
+
+    // --- Tests from origin/master ---
+
     [TestMethod]
     public void Query_EmptyTree_ReturnsEmpty()
     {
@@ -131,20 +262,6 @@ public void Query_AfterClear_ReturnsEmpty()
         Assert.AreEqual(0, results.Count);
     }
 
-    [TestMethod]
-    public void Query_Radius_ReturnsItemsWithinRadius()
-    {
-        var tree = new QuadTree<string>(DefaultBounds);
-        tree.Insert("CenterItem", new Vector2(50, 50));
-        tree.Insert("NearItem", new Vector2(55, 50));
-        tree.Insert("FarItem", new Vector2(80, 80));
-
-        var results = tree.Query(new Vector2(50, 50), 10f).ToList();
-
-        Assert.AreEqual(2, results.Count);
-        CollectionAssert.AreEquivalent(new[] { "CenterItem", "NearItem" }, results);
-    }
-
     [TestMethod]
     public void Insert_OutsideBounds_ReturnsFalseAndNotQueried()
     {