old_contents: 
  class TestInstall(object):
  
      def test_ceph_dir_exists(self, File):
          assert File('/etc/ceph').exists
  
      def test_ceph_dir_is_a_directory(self, File):
          assert File('/etc/ceph').is_directory
  
      def test_ceph_conf_exists(self, File):
          assert File('/etc/ceph/ceph.conf').exists
  
      def test_ceph_conf_is_a_file(self, File):
          assert File('/etc/ceph/ceph.conf').is_file
  
      def test_ceph_command_exists(self, Command):
          assert Command.exists("ceph")
  
  
  class TestCephConf(object):
  
      def test_ceph_config_has_inital_members_line(self, node, File):
          assert File("/etc/ceph/ceph.conf").contains("^mon initial members = .*$")
  
      def test_initial_members_line_has_correct_value(self, node, File):
          mons = ",".join("ceph-%s" % host
                          for host in node["vars"]["groups"]["mons"])
          line = "mon initial members = {}".format(mons)
          assert File("/etc/ceph/ceph.conf").contains(line)
  
      def test_ceph_config_has_mon_host_line(self, node, File):
          assert File("/etc/ceph/ceph.conf").contains("^mon host = .*$")
  
      def test_mon_host_line_has_correct_value(self, node, File):
          mon_ips = []
          for x in range(0, node["num_mons"]):
              mon_ips.append("{}.1{}".format(node["subnet"], x))
          line = "mon host = {}".format(",".join(mon_ips))
          assert File("/etc/ceph/ceph.conf").contains(line)
  
new_contents: 
  class TestInstall(object):
  
      def test_ceph_dir_exists(self, File):
          assert File('/etc/ceph').exists
  
      def test_ceph_dir_is_a_directory(self, File):
          assert File('/etc/ceph').is_directory
  
      def test_ceph_conf_exists(self, File, node):
          assert File(node["conf_path"]).exists
  
      def test_ceph_conf_is_a_file(self, File, node):
          assert File(node["conf_path"]).is_file
  
      def test_ceph_command_exists(self, Command):
          assert Command.exists("ceph")
  
  
  class TestCephConf(object):
  
      def test_ceph_config_has_inital_members_line(self, node, File):
          assert File(node["conf_path"]).contains("^mon initial members = .*$")
  
      def test_initial_members_line_has_correct_value(self, node, File):
          mons = ",".join("ceph-%s" % host
                          for host in node["vars"]["groups"]["mons"])
          line = "mon initial members = {}".format(mons)
          assert File(node["conf_path"]).contains(line)
  
      def test_ceph_config_has_mon_host_line(self, node, File):
          assert File(node["conf_path"]).contains("^mon host = .*$")
  
      def test_mon_host_line_has_correct_value(self, node, File):
          mon_ips = []
          for x in range(0, node["num_mons"]):
              mon_ips.append("{}.1{}".format(node["subnet"], x))
          line = "mon host = {}".format(",".join(mon_ips))
          assert File(node["conf_path"]).contains(line)
  
subject: use node["conf_path"] instead of hardcoding the path in tests