root@mta-system:~# cat /tmp/ordering.pp 
@user { "seph":
  ensure     => "present",
  uid        => "2001",
  comment    => "seph",
  home       => "/home/seph",
  shell      => "/bin/bash",
  allowdupe  => false,
  managehome => true,
  password   => '!!',
}

@ssh_authorized_key { "seph-2008":
  ensure  => present,
  key     => "foo==",
  type    => "ssh-dss",
  name    => "seph@macbook-2008",
  user    => seph,
  require => User[seph],
}

realize(
  User["seph"],
  Ssh_authorized_key["seph-2008"],
)


root@mta-system:~# puppet --verbose  --debug /tmp/ordering.pp 
info: Loading fact virtual
sh: Syntax error: Bad fd number
sh: Syntax error: Bad fd number
err: Could not create seph-2008: user seph doesn't exist
user seph doesn't exist