test {SUNION with non existing keys} {
lsort [$r sunion nokey1 set1 set2 nokey2]
} [lsort -uniq "[$r smembers set1] [$r smembers set2]"]
test {SUNION with non existing keys} {
lsort [$r sunion nokey1 set1 set2 nokey2]
} [lsort -uniq "[$r smembers set1] [$r smembers set2]"]