new_contents: import pytest
  import subprocess
  
  import ceph_deploy.rgw as rgw
  
  
  def test_help(tmpdir, cli):
      with cli(
          args=['ceph-deploy', 'rgw', '--help'],
          stdout=subprocess.PIPE,
          ) as p:
          result = p.stdout.read()
      assert 'usage: ceph-deploy rgw' in result
      assert 'positional arguments' in result
      assert 'optional arguments' in result
  
  
  def test_bad_no_conf(tmpdir, cli):
      with tmpdir.join('ceph.conf').open('w'):
          pass
      with pytest.raises(cli.Failed) as err:
          with cli(
              args=['ceph-deploy', 'rgw'],
              stderr=subprocess.PIPE,
              ) as p:
              result = p.stderr.read()
      assert 'usage: ceph-deploy rgw' in result
      assert err.value.status == 2
  
  
  def test_rgw_prefix_auto():
      daemon = rgw.colon_separated("hostname")
      assert daemon == ("hostname", "rgw.hostname")
  
  
  def test_rgw_prefix_custom():
      daemon = rgw.colon_separated("hostname:mydaemon")
      assert daemon == ("hostname", "rgw.mydaemon")
  
subject: Add tests for RGW daemon naming