+my ( $ISBN_letter ) = grep {$_->{code} eq 'ISBN'} @$letters;
+is( $ISBN_letter->{name}, 'book', 'letter name for "ISBN" letter is book' );
+is( scalar( @$letters ), 2, 'GetLetters returns the 2 inserted letters' );
+
+# Regression test for bug 10843
+# $dt->add takes a scalar, not undef
+my $letter;
+t::lib::Mocks::mock_preference('ReservesMaxPickUpDelay', undef);
+$letter = C4::Letters::_parseletter( undef, 'reserves', {waitingdate => "2013-01-01"} );
+is( ref($letter), 'HASH');
+t::lib::Mocks::mock_preference('ReservesMaxPickUpDelay', 1);
+$letter = C4::Letters::_parseletter( undef, 'reserves', {waitingdate => "2013-01-01"} );
+is( ref($letter), 'HASH');
+
+1;