Add tests for #729

StackExchange.Redis.Tests/Scans.cs

@@ -315,6 +315,45 @@ public void HashScanLarge(int pageSize)
             }
         }
 
+        [Fact] // See https://github.com/StackExchange/StackExchange.Redis/issues/729
+        public void HashScanThresholds()
+        {
+            using (var conn = Create(allowAdmin: true))
+            {
+                var config = conn.GetServer(conn.GetEndPoints(true)[0]).ConfigGet("hash-max-ziplist-entries").First();
+                var threshold = int.Parse(config.Value);
+
+                RedisKey key = Me();
+                Assert.False(GotCursors(conn, key, threshold - 1));
+                Assert.True(GotCursors(conn, key, threshold + 1));
+            }
+        }
+
+        private bool GotCursors(ConnectionMultiplexer conn, RedisKey key, int count)
+        {
+            var db = conn.GetDatabase();
+            db.KeyDelete(key);
+
+            var entries = new HashEntry[count];
+            for (var i = 0; i < count; i++)
+            {
+                entries[i] = new HashEntry("Item:" + i, i);
+            }
+            db.HashSet(key, entries);
+
+            var found = false;
+            var response = db.HashScan(key);
+            var cursor = ((IScanningCursor)response);
+            foreach (var i in response)
+            {
+                if (cursor.Cursor > 0)
+                {
+                    found = true;
+                }
+            }
+            return found;
+        }
+
         [Theory]
         [InlineData(10)]
         [InlineData(100)]