diff --git a/lib/ansi.ml b/lib/ansi.ml
index 1076180..9f766a0 100644
--- a/lib/ansi.ml
+++ b/lib/ansi.ml
@@ -29,10 +29,10 @@ let ansi_sgr =
       'h';
       'l';
     ]
-  in
+  and (=?) = List.mem in
   peek_char >>= function
   | Some c ->
-      if List.mem c valid then advance 1 *> return (Some c) else return None
+      if c =? valid then advance 1 *> return (Some c) else return None
   | None -> return None
 
 let capture_ansi = both ansi_values ansi_sgr
@@ -40,12 +40,6 @@ let capture_ansi = both ansi_values ansi_sgr
 let ansi_parse =
   ansi_escape *> capture_ansi
   
-let%test "ansi_parse" =
-  parse_string ~consume:Angstrom.Consume.Prefix ansi_parse "\x1b[35;23;12m"
-  |> function
-  | Ok (d, t) -> d = [ 35; 23; 12 ] && t = Some 'm'
-  | _ -> false
-
 type parser_state_colour = ParsingFg | ParsingBg
 
 type parser_state =
@@ -100,6 +94,12 @@ let parse_ansi_intermediate (codes, terminator) : chunk =
   in
   Ansi final
 
+let%test "ansi_parse" =
+  parse_string ~consume:Angstrom.Consume.Prefix ansi_parse "\x1b[35;23;12m"
+  |> function
+  | Ok (d, t) -> d = [ 35; 23; 12 ] && t = Some 'm'
+  | _ -> false
+
 let%test "ansi_intermediate_parse" =
   let result =
     parse_ansi_intermediate ([ 38; 5; 25; 24; 23; 1; 0 ], Some 'm')