Fix combine bug for triangular bounding boxes

lib/ddrt/dynamic_rtree_impl/utils.ex

@@ -89,15 +89,19 @@ defmodule DDRT.DynamicRtreeImpl.Utils do
   end
 
   # Return the area of a bounding box
-  def area([{a, b}, {c, d}]) when (b - a) * (d - c) != 0 do
-    (b - a) * (d - c)
-  end
-
-  def area([{_a, _b}, {_c, _d}]) do
-    -1
+  def area([{a, b}, {c, d}]) do
+    ab = b - a
+    cd = d - c
+
+    cond do
+      ab == 0 and cd != 0 -> cd
+      ab != 0 and cd == 0 -> ab
+      ab != 0 and cd != 0 -> ab * cd
+      ab == 0 and cd == 0 -> -1
+    end
   end
 
-  # Return de the middle bounding box value
+  # Return the middle bounding box value
   def middle_value([{a, b}, {c, d}]) do
     (a + b + c + d) / 2
   end

test/drtree_test.exs

@@ -90,30 +90,18 @@ defmodule DynamicRtreeTest do
       assert root_box == [{-50, 36}, {-10, 41}]
     end
 
-    test "MerkleMap inserts a same single point without crash" do
-      DynamicRtree.new(type: MerkleMap)
-      new_tuple = {new_node, _new_box} = {UUID.uuid1(), [{1, 2}, {3, 4}]}
-      {:ok, t} = DynamicRtree.insert(new_tuple)
-      assert t == DynamicRtree.tree()
-      {cont, parent, box} = t |> MerkleMap.get(new_node)
-      assert cont == :leaf
-      assert parent == t[:root]
-      assert box == [{1, 2}, {3, 4}]
-
+    test "MerkleMap inserts a triangular bounding box without crash" do
       DynamicRtree.new(type: MerkleMap)
 
-      # ok:
-      # {:ok, t} = DynamicRtree.insert({1, [{9, 9.1}, {9, 9.1}]})
-      # crash:
       {:ok, t} = DynamicRtree.insert({1, [{9, 9}, {9, 9.1}]})
 
       assert t == DynamicRtree.tree()
 
       root = t |> MerkleMap.get(:root)
       {ch, _root_ptr, root_box} = t |> MerkleMap.get(root)
       assert t |> Enum.to_list() |> length == t |> Enum.uniq() |> length
-      assert length(ch) == 2
-      assert root_box == [{-50, 36}, {-10, 41}]
+      assert length(ch) == 1
+      assert root_box == [{9, 9}, {9, 9.1}]
     end
 
     test "Map delete leaf keeps tree consistency" do
@@ -141,7 +129,7 @@ defmodule DynamicRtreeTest do
       refute delete_id in (t[old_parent] |> elem(0))
 
       {:ok, same_t} = DynamicRtree.delete(delete_id)
-      assert t = same_t
+      assert ^t = same_t
 
       {:ok, t} = DynamicRtree.delete(1..100 |> Enum.map(fn x -> x end))
       root = t[:root]
@@ -180,7 +168,7 @@ defmodule DynamicRtreeTest do
       refute delete_id in (t |> MerkleMap.get(old_parent) |> elem(0))
 
       {:ok, same_t} = DynamicRtree.delete(delete_id)
-      assert t = same_t
+      assert ^t = same_t
 
       {:ok, t} = DynamicRtree.delete(1..100 |> Enum.map(fn x -> x end))
       root = t |> MerkleMap.get(:root)