PdoPgsql tests

[Danack]

Hi @tontonsb,

So, I just added all of the PdoPgsql methods in commit #83bb08c495cee0cc9d234296d70f8c009de6b95b

There are quite a few existing tests for these methods against the PDO class. It doesn't feel right to just copy all of these tests, as that would be a lot of duplication.

Do you want to have a think as see if you can come up with a cunning way to run the existing tests both with the DB connection construction going through PDO::connect, rather than new PDO() as well as with the current new PDO().

Eventually the versions of the methods on the PDO class will be deprecated and removed, probably.