my @dieings;
my @warnings;
my $rc;

eval {
  local $SIG{__WARN__} = sub {push @warnings, @_};
  local $SIG{__DIE__ } = sub {push @dieings , @_};

  $rc = $obj->method(@params);
}

is(@warnings, $expectedWarningCount, 'correct number of warnings raised');
like(shift(@warnings), qr/expected pattern of first warning/, 'first warning message correct');
like(shift(@warnings), qr/expected pattern of second warning/, 'second warning message correct');
...
is(@dieings, $expectedDeathCount, 'correct number of deaths raised');
like(shift(@dieings), qr/expected pattern of first death/, 'first death message correct');
...
is($rc, $expectReturnValue, 'method returned required value');
# or, if method returns an object
isa_ok($rc, 'Expect::Class', 'received expected class');
...