package db;

# db.pm

use strict;
use warnings;

use Data::Dumper;
use DBI;
our $dbh = undef;

sub connect {
  $dbh = DBI->connect('DBI:mysql:test', '', '') 
        or die "connect failed";
}

sub disconnect {
  $dbh->disconnect();
}

sub select_i_from_t {
  my $sth = $dbh->prepare(q{select i from t}) or die "prepare failed";
  $sth->execute() or die "execute failed";
  my $arref = [];
    if ($sth && !$sth->errstr()) {  # <-- errstr is always be false in
                                  # <-- Mocked mode 
        while (my $row = $sth->fetchrow_arrayref()) {
            push @$arref, $row->[0];
        }
    } else {
        die "no sth" if (!$sth);
        die "errstr:" . $sth->errstr() if ($sth->errstr());
    }
  return $arref;
}

1;

__END__

# db.t

use strict;
use warnings;

# Signal the we want to use Test::MockDBI
BEGIN { push @ARGV, "--dbitest=42"; }

use Data::Dumper;
use Test::More;
use Test::MockDBI;

BEGIN { plan tests => 4 }

use_ok(q{db});
my $mock_dbi = Test::MockDBI::get_instance();

# Replace the code for sub errstr in Test::MockDBI.
# Code is from Test::MockObject (CPAN)
{
    ## no critic (ProhibitNoStrict)
    no warnings 'redefine';
    no strict 'refs';
    *{ Test::MockDBI::errstr } = sub { return };
}

my $vals = [ [123], [124], [125] ];
$mock_dbi->set_retval_scalar(
  42,
  "select i from t",
  sub { shift @$vals }
);

ok(defined(db::connect()), q{Expect connect() to return true});

is_deeply(
  db::select_i_from_t(),
  [ 123, 124, 125 ],
  q{Expect select_i_from_t() to return arrayref [ 123, 124, 125 ]}
);

ok(defined(db::disconnect()), q{Expect disconnect() to return true});


__END__
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