Use a set of helper/parsing classes to perform system configuration

Previously file modification of system configuration was done
in a functional and hard to test manner. Now instead this patch
allows for a manner that provides a nice object oriented
interface to those objects as well as makes it possible to test
those parsing entities without having to invoke distro class code.
   - Created parsers for:
    - /etc/sysconfig
    - /etc/hostname
    - resolv.conf
    - /etc/hosts

Moved duplicated functionality into the root level distro class including:
 - apply_hostname
 - set_hostname
 - *various shared configuration file names/paths*

1 files changed, 38 insertions, 0 deletions

diff --git a/tests/unittests/test_distros/test_hostname.py b/tests/unittests/test_distros/test_hostname.py
new file mode 100644
index 00000000..8e644f4d
--- /dev/null
+++ b/tests/unittests/test_distros/test_hostname.py
@@ -0,0 +1,38 @@
+from mocker import MockerTestCase
+
+from cloudinit.distros.parsers import hostname
+
+
+BASE_HOSTNAME = '''
+# My super-duper-hostname
+
+blahblah
+
+'''
+BASE_HOSTNAME = BASE_HOSTNAME.strip()
+
+
+class TestHostnameHelper(MockerTestCase):
+    def test_parse_same(self):
+        hn = hostname.HostnameConf(BASE_HOSTNAME)
+        self.assertEquals(str(hn).strip(), BASE_HOSTNAME)
+        self.assertEquals(hn.hostname, 'blahblah')
+
+    def test_no_adjust_hostname(self):
+        hn = hostname.HostnameConf(BASE_HOSTNAME)
+        prev_name = hn.hostname
+        hn.set_hostname("")
+        self.assertEquals(hn.hostname, prev_name)
+
+    def test_adjust_hostname(self):
+        hn = hostname.HostnameConf(BASE_HOSTNAME)
+        prev_name = hn.hostname
+        self.assertEquals(prev_name, 'blahblah')
+        hn.set_hostname("bbbbd")
+        self.assertEquals(hn.hostname, 'bbbbd')
+        expected_out = '''
+# My super-duper-hostname
+
+bbbbd
+'''
+        self.assertEquals(str(hn).strip(), expected_out.strip())