diff --git a/tests/integrated.ml b/tests/integrated.ml
index 70468d5..45beba0 100644
--- a/tests/integrated.ml
+++ b/tests/integrated.ml
@@ -156,7 +156,7 @@ let refname name =
 
 let reference name =
   if Sys.file_exists name then
-    let inc = open_in name in
+    let inc = open_in_bin name in
     really_input_string inc (in_channel_length inc)
   else
     ""