From d506334b678ea1f0ad2f28b1144365ac7751999a Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Thu, 2 Aug 2018 14:14:39 +0200
Subject: [PATCH] Test: new sorted set skiplist order consistency.

This should be able to find new bugs and regressions about the new
sorted set update function when ZADD is used to update an element
already existing.

The test is able to find the bug fixed at 2f282aee immediately.
---
 tests/unit/type/zset.tcl | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/tests/unit/type/zset.tcl b/tests/unit/type/zset.tcl
index bebba96d9..cf54ae839 100644
--- a/tests/unit/type/zset.tcl
+++ b/tests/unit/type/zset.tcl
@@ -1185,4 +1185,30 @@ start_server {tags {"zset"}} {
         stressers ziplist
         stressers skiplist
     }
+
+    test {ZSET skiplist order consistency when elements are moved} {
+        set original_max [lindex [r config get zset-max-ziplist-entries] 1]
+        r config set zset-max-ziplist-entries 0
+        for {set times 0} {$times < 10} {incr times} {
+            r del zset
+            for {set j 0} {$j < 1000} {incr j} {
+                r zadd zset [randomInt 50] ele-[randomInt 10]
+            }
+
+            # Make sure that element ordering is correct
+            set prev_element {}
+            set prev_score -1
+            foreach {element score} [r zrange zset 0 -1 WITHSCORES] {
+                # Assert that elements are in increasing ordering
+                assert {
+                    $prev_score < $score ||
+                    ($prev_score == $score &&
+                     [string compare $prev_element $element] == -1)
+                }
+                set prev_element $element
+                set prev_score $score
+            }
+        }
+        r config set zset-max-ziplist-entries $original_max
+    }
 }