>> I would suggest to add that to https://wiki.postgresql.org/wiki/Todo.
>>
>> I may look into it when I have time, over the summer. The key point is
>> that there is no need for a temporary installation, but only of a
>> temporary cluster, and to trick this cluster into loading the
>> uninstalled extension, maybe by playing with dynamic_library_path in
>> the temporary cluster.
>
> The temporary cluster will be in a temporarty `initdb`ed directory, no?
Yep.
> If so, you can just install the extension there.
I'm not sure the extension is sought for in the cluster (ie the database
data directory). If you do "make install" the shared object is installed
in some /usr/lib/postgresql/... directory (under unix), and it is loaded
from there, but I understood that you wanted to test WITHOUT installing
against the current postgresql.
--
Fabien.