+ assert_equal 0 [r setnx x 20]
+ assert_equal 10 [r get x]
+ }
+
+ test "SETNX against expired volatile key" {
+ # Make it very unlikely for the key this test uses to be expired by the
+ # active expiry cycle. This is tightly coupled to the implementation of
+ # active expiry and dbAdd() but currently the only way to test that
+ # SETNX expires a key when it should have been.
+ for {set x 0} {$x < 9999} {incr x} {
+ r setex key-$x 3600 value
+ }
+
+ # This will be one of 10000 expiring keys. A cycle is executed every
+ # 100ms, sampling 10 keys for being expired or not. This key will be
+ # expired for at most 1s when we wait 2s, resulting in a total sample
+ # of 100 keys. The probability of the success of this test being a
+ # false positive is therefore approx. 1%.
+ r set x 10
+ r expire x 1
+
+ # Wait for the key to expire
+ after 2000
+
+ assert_equal 1 [r setnx x 20]
+ assert_equal 20 [r get x]
+ }