public void FindLeafToInsertKey_NewKeySmallerThanAllKeysInTree_ExpectsTheSparseLeafNodeContainingSmallestKey()
        {
            var leaf = _tree.FindLeafToInsertKey(_tree.Root, 5);

            Assert.AreEqual(2, leaf.KeyCount);
            Assert.IsTrue(leaf.IsLeaf());
            Assert.AreEqual(10, leaf.GetKey(0));
            Assert.AreEqual(20, leaf.GetKey(1));
        }