diff --git a/tests/unit/cluster/slot-stats.tcl b/tests/unit/cluster/slot-stats.tcl
index 2724ed5195..9860dfb539 100644
--- a/tests/unit/cluster/slot-stats.tcl
+++ b/tests/unit/cluster/slot-stats.tcl
@@ -388,6 +388,7 @@ start_cluster 1 0 {tags {external:skip cluster}} {
         # SET key value\r\n --> 15 bytes.
         $rd write "SET $key value\r\n"
         $rd flush
+        assert_equal OK [$rd read]
 
         set slot_stats [R 0 CLUSTER SLOT-STATS SLOTSRANGE 0 16383]
         set expected_slot_stats [