Failing regression tests for #340

apps/indexer/lib/indexer/block_fetcher.ex

@@ -274,7 +274,8 @@ defmodule Indexer.BlockFetcher do
     |> chunk_ranges(blocks_batch_size)
   end
 
-  defp chunk_ranges(ranges, size) do
+  @doc false
+  def chunk_ranges(ranges, size) do
     Enum.flat_map(ranges, fn
       first..last = range when last - first <= size ->
         [range]

apps/indexer/test/indexer/block_fetcher_test.exs

@@ -829,6 +829,68 @@ defmodule Indexer.BlockFetcherTest do
     end
   end
 
+  describe "chunk_ranges/2" do
+    test "with first < last in one chunk" do
+      range = 0..1
+      size = 2
+
+      assert Enum.count(range) <= size
+      assert BlockFetcher.chunk_ranges([range], size) == [range]
+    end
+
+    test "with first < last with filled last chunk" do
+      range = 0..1
+      size = 1
+
+      assert Enum.count(range) > size
+      assert rem(Enum.count(range), size) == 0
+      assert BlockFetcher.chunk_ranges([range], size) == [0..0, 1..1]
+    end
+
+    test "with first < last with unfilled last chunk" do
+      range = 0..2
+      size = 2
+
+      assert Enum.count(range) > size
+      refute rem(Enum.count(range), size) == 0
+      assert BlockFetcher.chunk_ranges([range], size) == [0..1, 2..2]
+    end
+
+    test "with first == last" do
+      range = 0..0
+      size = 1
+
+      assert Enum.count(range) == size
+      assert BlockFetcher.chunk_ranges([range], size) == [range]
+    end
+
+    test "with first > last in one chunk" do
+      range = 1..0
+      size = 2
+
+      assert Enum.count(range) <= size
+      assert BlockFetcher.chunk_ranges([range], size) == [range]
+    end
+
+    test "with first > last with filled last chunk" do
+      range = 1..0
+      size = 1
+
+      assert Enum.count(range) > size
+      assert rem(Enum.count(range), size) == 0
+      assert BlockFetcher.chunk_ranges([range], size) == [1..1, 0..0]
+    end
+
+    test "with first > last with unfilled last chunk" do
+      range = 2..0
+      size = 2
+
+      assert Enum.count(range) > size
+      refute rem(Enum.count(range), size) == 0
+      assert BlockFetcher.chunk_ranges([range], size) == [2..1, 0..0]
+    end
+  end
+
   defp capture_log_at_level(level, block) do
     logger_level_transaction(fn ->
       Logger.configure(level: level)