You probably should use Test::Cmd if you want to integrate easily with Test::More and friends. In Test::Cmd::Common (to quote from the docs):

All methods throw exceptions and exit on failure

Since you want to detect failure rather than exit, use Test::Cmd instead. For example:

use strict;
use warnings;
use Test::More tests => 2;
use Test::Cmd;

my $cmd = Test::Cmd->new( prog => '/bin/ls /etc/motd' );
is $cmd->run, 0, 'ls ran okay';
is $cmd->stdout, "/etc/motd\n", 'and gave expected output';
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