2 files changed, 20 insertions, 0 deletions
diff --git a/test/gleam/iterator_test.gleam b/test/gleam/iterator_test.gleam
index 81a2908..492bb1e 100644
--- a/test/gleam/iterator_test.gleam
+++ b/test/gleam/iterator_test.gleam
@@ -373,3 +373,13 @@ pub fn group_test() {
     tuple(2, [2, 5]),
   ]))
 }
+
+pub fn reduce_test() {
+  iterator.from_list([])
+  |> iterator.reduce(with: fn(x, y) { x + y })
+  |> should.equal(Error(Nil))
+
+  iterator.from_list([1, 2, 3, 4, 5])
+  |> iterator.reduce(with: fn(x, y) { x + y })
+  |> should.equal(Ok(15))
+}
diff --git a/test/gleam/list_test.gleam b/test/gleam/list_test.gleam
index b7470ac..fc8ea11 100644
--- a/test/gleam/list_test.gleam
+++ b/test/gleam/list_test.gleam
@@ -612,3 +612,13 @@ pub fn sized_chunk_test() {
   |> list.sized_chunk(into: 3)
   |> should.equal([[1, 2, 3], [4, 5, 6], [7, 8]])
 }
+
+pub fn reduce_test() {
+  []
+  |> list.reduce(with: fn(x, y) { x + y })
+  |> should.equal(Error(Nil))
+
+  [1, 2, 3, 4, 5]
+  |> list.reduce(with: fn(x, y) { x + y })
+  |> should.equal(Ok(15))
+}