class testing ( $file = 'testing' ) {
        file { "/tmp/$file":
          ensure => present,
          mode => 0777,
          content => "Testing123"
        }
}
node default {
        file {'/tmp/example-ip':                                            # resource type file and filename
          ensure  => present,                                               # make sure it exists
          mode    => 0644,                                                  # file permissions
          content => "Here is my Public IP Address: ${ipaddress_eth0}.\n",  # note the ipaddress_eth0 fact
        }
}

node "office.example.com" {
        class { 'testing' :
                $file => 'Testing123',
        }
}