DBI connect fails with DBD-Pg-2.12.0 but works with DBD-Pg-2.11.8

Hi.  I'd like to upgrade our version of DBD::Pg from 2.11.8 to 2.12.0  
(or higher), but 2.12.0 (the version I get when I upgrade DBD::Pg from  
CPAN) results in a connection error that did not occur with the  
earlier versions.  Specifically, when I attempt to run my test scripts  
all my connection attempts fail with error messages like:

DBI connect('dbname=postgres','dev',...) failed: FATAL:  role "dev"  
does not exist at t/read.t line 442

The source code line for referred to by this error message is

   my $pgh = DBI->connect(
                           'dbi:Pg:dbname=postgres',
                           'dev', '',
                           +{
                              AutoCommit => 1,
                              RaiseError => 1,
                              PrintError => 0,
                              PrintWarn  => 0,
                            }
                         );


As far as I know, there is only one Pg server running on localhost,  
and it uses the standard port.  For this server, contrary to what the  
error message above says, the "dev" role most definitely exists.  In  
fact, to get these errors to disappear (and all the tests to pass) all  
I need to do is ensure that the version of DBD::Pg that the code uses  
is 2.11.8 instead of 2.12.0, which confirms that role "dev" does exist  
as expected.

Does DBD-Pg-2.12.0 need a specific version of DBI?  I'm using 1.607.

How can I troubleshoot this further?

Thanks in advance,

Gabriel Berriz