diff --git a/tests/unit/dune b/tests/unit/dune
index 7be0c4d9..b4ceef08 100644
--- a/tests/unit/dune
+++ b/tests/unit/dune
@@ -1,5 +1,5 @@
 
 (tests
-  (names t_util t_buf t_server)
+  (names t_util t_buf t_server t_io)
   (package tiny_httpd)
   (libraries tiny_httpd.core qcheck-core qcheck-core.runner test_util))
diff --git a/tests/unit/t_io.ml b/tests/unit/t_io.ml
new file mode 100644
index 00000000..61400b4d
--- /dev/null
+++ b/tests/unit/t_io.ml
@@ -0,0 +1,24 @@
+open Test_util
+open Tiny_httpd_core.IO
+
+let spf = Printf.sprintf
+
+(* one chunk *)
+let () =
+  let io = Input.of_string "5\r\nhello\r\n0\r\n\r\nARGH" in
+  let str =
+    io
+    |> Input.read_chunked ~bytes:(Bytes.create 4) ~fail:failwith
+    |> Input.read_all_using ~buf:(Buf.create ())
+  in
+  assert_eq ~to_string:(spf "%S") "hello" str
+
+(* two chunks *)
+let () =
+  let io = Input.of_string "5\r\nhello\r\n6\r\n world\r\n0\r\n\r\nARGH" in
+  let str =
+    io
+    |> Input.read_chunked ~bytes:(Bytes.create 4) ~fail:failwith
+    |> Input.read_all_using ~buf:(Buf.create ())
+  in
+  assert_eq ~to_string:(spf "%S") "hello world" str