diff --git a/tests/suites.c b/tests/suites.c
index f23c116cc..2028bca51 100644
--- a/tests/suites.c
+++ b/tests/suites.c
@@ -361,7 +361,7 @@ static void test_harness(void* vargs)
         fname = args->argv[1];
     }
 
-    file = fopen(fname, "r");
+    file = fopen(fname, "rb");
     if (file == NULL) {
         fprintf(stderr, "unable to open %s\n", fname);
         args->return_code = 1;