Improve coverage and fix regression on Stream.chunk/4

Author: José Valim

lib/elixir/lib/stream.ex

@@ -129,7 +129,7 @@ defmodule Stream do
   @doc false
   def chunk(enum, n, step, leftover \\ nil)
       when is_integer(n) and n > 0 and is_integer(step) and step > 0 do
-    R.chunk(&chunk_while/4, enum, n, step, leftover)
+    chunk_every(enum, n, step, leftover || :discard)
   end
 
   @doc """

lib/elixir/test/elixir/enum_test.exs

@@ -59,6 +59,19 @@ defmodule EnumTest do
     assert Enum.chunk([1, 2, 3, 4, 5], 4, 4, 6..10) == [[1, 2, 3, 4], [5, 6, 7, 8]]
   end
 
+  test "chunk_every/2" do
+    assert Enum.chunk_every([1, 2, 3, 4, 5], 2) == [[1, 2], [3, 4], [5]]
+  end
+
+  test "chunk_every/4" do
+    assert Enum.chunk_every([1, 2, 3, 4, 5], 2, 2, [6]) == [[1, 2], [3, 4], [5, 6]]
+    assert Enum.chunk_every([1, 2, 3, 4, 5, 6], 3, 2, :discard) == [[1, 2, 3], [3, 4, 5]]
+    assert Enum.chunk_every([1, 2, 3, 4, 5, 6], 2, 3, :discard) == [[1, 2], [4, 5]]
+    assert Enum.chunk_every([1, 2, 3, 4, 5, 6], 3, 2, []) == [[1, 2, 3], [3, 4, 5], [5, 6]]
+    assert Enum.chunk_every([1, 2, 3, 4, 5, 6], 3, 3, []) == [[1, 2, 3], [4, 5, 6]]
+    assert Enum.chunk_every([1, 2, 3, 4, 5], 4, 4, 6..10) == [[1, 2, 3, 4], [5, 6, 7, 8]]
+  end
+
   test "chunk_by/2" do
     assert Enum.chunk_by([1, 2, 2, 3, 4, 4, 6, 7, 7], &(rem(&1, 2) == 1)) == [[1], [2, 2], [3], [4, 4, 6], [7, 7]]
     assert Enum.chunk_by([1, 2, 3, 4], fn _ -> true end) == [[1, 2, 3, 4]]
@@ -828,6 +841,18 @@ defmodule EnumTest.Range do
     assert Enum.at(2..6, -8) == nil
   end
 
+  test "chunk/2" do
+    assert Enum.chunk(1..5, 2) == [[1, 2], [3, 4]]
+  end
+
+  test "chunk/4" do
+    assert Enum.chunk(1..5, 2, 2, [6]) == [[1, 2], [3, 4], [5, 6]]
+    assert Enum.chunk(1..6, 3, 2) == [[1, 2, 3], [3, 4, 5]]
+    assert Enum.chunk(1..6, 2, 3) == [[1, 2], [4, 5]]
+    assert Enum.chunk(1..6, 3, 2, []) == [[1, 2, 3], [3, 4, 5], [5, 6]]
+    assert Enum.chunk(1..5, 4, 4, 6..10) == [[1, 2, 3, 4], [5, 6, 7, 8]]
+  end
+
   test "chunk_every/2" do
     assert Enum.chunk_every(1..5, 2) == [[1, 2], [3, 4], [5]]
   end

lib/elixir/test/elixir/stream_test.exs

@@ -42,6 +42,23 @@ defmodule StreamTest do
     assert Enum.to_list(stream) == [3, 5, 7]
   end
 
+  test "chunk/2, chunk/3 and chunk/4" do
+    assert Stream.chunk([1, 2, 3, 4, 5], 2) |> Enum.to_list ==
+           [[1, 2], [3, 4]]
+    assert Stream.chunk([1, 2, 3, 4, 5], 2, 2, [6]) |> Enum.to_list ==
+           [[1, 2], [3, 4], [5, 6]]
+    assert Stream.chunk([1, 2, 3, 4, 5, 6], 3, 2) |> Enum.to_list ==
+           [[1, 2, 3], [3, 4, 5]]
+    assert Stream.chunk([1, 2, 3, 4, 5, 6], 2, 3) |> Enum.to_list ==
+           [[1, 2], [4, 5]]
+    assert Stream.chunk([1, 2, 3, 4, 5, 6], 3, 2, []) |> Enum.to_list ==
+           [[1, 2, 3], [3, 4, 5], [5, 6]]
+    assert Stream.chunk([1, 2, 3, 4, 5, 6], 3, 3, []) |> Enum.to_list ==
+           [[1, 2, 3], [4, 5, 6]]
+    assert Stream.chunk([1, 2, 3, 4, 5], 4, 4, 6..10) |> Enum.to_list ==
+           [[1, 2, 3, 4], [5, 6, 7, 8]]
+  end
+
   test "chunk_every/2, chunk_every/3 and chunk_every/4" do
     assert Stream.chunk_every([1, 2, 3, 4, 5], 2) |> Enum.to_list ==
            [[1, 2], [3, 4], [5]]