diff --git a/tests/support/redis.tcl b/tests/support/redis.tcl
index 36b005a17754182ef8cd76cad5e1fea3667efcbf..fae48eaa0752dfa9d493a53b3aba8a27666462dd 100644
--- a/tests/support/redis.tcl
+++ b/tests/support/redis.tcl
@@ -170,7 +170,10 @@ proc ::redis::redis_read_reply fd {
         - {return -code error [redis_read_line $fd]}
         $ {redis_bulk_read $fd}
         * {redis_multi_bulk_read $fd}
-        default {return -code error "Bad protocol, '$type' as reply type byte"}
+        default {
+            if {$type eq {}} {return -code error "I/O error reading reply"}
+            return -code error "Bad protocol, '$type' as reply type byte"
+        }
     }
 }