Documentation on clustertest configuration (https://github.com/ssinger/slony1-engine/blob/clustertest/clustertest/conf/databases.properties) indicates:
# Users with superuser rights that slony will work with
This contradicts Slony documentation:
It is reasonable for some tests to have the replication user given superuser capabilities, but we should have at least one (possibly most!) tests that validate that replication works fine when the replication user is only given weak capabilities.